mirror of
https://github.com/apache/impala.git
synced 2025-12-25 02:03:09 -05:00
c5104d3d5b
Change-Id: I32b6d146f0a78abdeb28cb103edcab847fe5b9da Reviewed-on: http://gerrit.cloudera.org:8080/14876 Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Reviewed-by: Alex Rodoni <arodoni@cloudera.com>
1361 lines
48 KiB
XML
1361 lines
48 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!--
|
|
Licensed to the Apache Software Foundation (ASF) under one
|
|
or more contributor license agreements. See the NOTICE file
|
|
distributed with this work for additional information
|
|
regarding copyright ownership. The ASF licenses this file
|
|
to you under the Apache License, Version 2.0 (the
|
|
"License"); you may not use this file except in compliance
|
|
with the License. You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing,
|
|
software distributed under the License is distributed on an
|
|
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
|
KIND, either express or implied. See the License for the
|
|
specific language governing permissions and limitations
|
|
under the License.
|
|
-->
|
|
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
|
|
<concept id="conversion_functions">
|
|
|
|
<title>Impala Type Conversion Functions</title>
|
|
|
|
<titlealts audience="PDF">
|
|
|
|
<navtitle>Type Conversion Functions</navtitle>
|
|
|
|
</titlealts>
|
|
|
|
<prolog>
|
|
<metadata>
|
|
<data name="Category" value="Impala"/>
|
|
<data name="Category" value="Impala Functions"/>
|
|
<data name="Category" value="Impala Data Types"/>
|
|
<data name="Category" value="SQL"/>
|
|
<data name="Category" value="Data Analysts"/>
|
|
<data name="Category" value="Developers"/>
|
|
<data name="Category" value="Querying"/>
|
|
</metadata>
|
|
</prolog>
|
|
|
|
<conbody>
|
|
|
|
<p>
|
|
Conversion functions are typically used in combination with other functions to explicitly
|
|
pass the expected data types. Impala has strict rules regarding data types for function
|
|
parameters. For example, Impala does not automatically convert a <codeph>DOUBLE</codeph>
|
|
value to <codeph>FLOAT</codeph>, a <codeph>BIGINT</codeph> value to <codeph>INT</codeph>,
|
|
or other conversion where precision could be lost or overflow could occur. Also, for
|
|
reporting or dealing with loosely defined schemas in big data contexts, you might need to
|
|
convert values to or from the <codeph>STRING</codeph> type.
|
|
</p>
|
|
|
|
<p>
|
|
<b>Function reference:</b>
|
|
</p>
|
|
|
|
<p>
|
|
Impala supports the following type conversion functions:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>
|
|
<xref href="#conversion_functions/cast">CAST</xref>
|
|
</li>
|
|
|
|
<li>
|
|
<xref href="#conversion_functions/typeof">TYPEOF</xref>
|
|
</li>
|
|
</ul>
|
|
|
|
<dl>
|
|
<dlentry id="cast">
|
|
|
|
<dt>
|
|
CAST(expression AS type)
|
|
</dt>
|
|
|
|
<dd>
|
|
<b>Purpose:</b> Returns <varname>expression</varname> converted to the
|
|
<varname>type</varname> data type.
|
|
<p>
|
|
If the <varname>expression</varname> value is of a type that cannot be converted to
|
|
the target <varname>type</varname>:
|
|
<ul>
|
|
<li>
|
|
Of <codeph>DECIMAL</codeph>, <codeph>DATE</codeph>, and
|
|
<codeph>BOOLEAN</codeph>, the function returns an error.
|
|
</li>
|
|
|
|
<li>
|
|
Of all other types, the function returns <codeph>NULL</codeph>.
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
<p>
|
|
<b>Usage notes:</b>
|
|
</p>
|
|
|
|
<p>
|
|
Use <codeph>CAST</codeph> when passing a column value or literal to a function that
|
|
expects a parameter with a different type. Frequently used in SQL operations such as
|
|
<codeph>CREATE TABLE AS SELECT</codeph> and <codeph>INSERT ... VALUES</codeph> to
|
|
ensure that values from various sources are of the appropriate type for the
|
|
destination columns.
|
|
</p>
|
|
|
|
<p>
|
|
Where practical, do a one-time <codeph>CAST()</codeph> operation during the
|
|
ingestion process to make each column into the appropriate type, rather than using
|
|
many <codeph>CAST()</codeph> operations in each query; doing type conversions for
|
|
each row during each query can be expensive for tables with millions or billions of
|
|
rows.
|
|
</p>
|
|
|
|
<p
|
|
conref="../shared/impala_common.xml#common/timezone_conversion_caveat"/>
|
|
|
|
<p conref="../shared/impala_common.xml#common/related_info"/>
|
|
|
|
<p>
|
|
For details of casts from each kind of data type, see the description of the
|
|
appropriate type: <xref
|
|
href="impala_tinyint.xml#tinyint"/>,
|
|
<xref
|
|
href="impala_smallint.xml#smallint"/>,
|
|
<xref
|
|
href="impala_int.xml#int"/>,
|
|
<xref href="impala_bigint.xml#bigint"
|
|
/>,
|
|
<xref href="impala_float.xml#float"/>,
|
|
<xref
|
|
href="impala_double.xml#double"/>,
|
|
<xref
|
|
href="impala_decimal.xml#decimal">DECIMAL Data Type</xref>,
|
|
<xref
|
|
href="impala_string.xml#string"/>,
|
|
<xref
|
|
href="impala_char.xml#char">CHAR Data Type</xref>,
|
|
<xref
|
|
href="impala_varchar.xml#varchar">VARCHAR Data Type</xref>,
|
|
<xref
|
|
href="impala_timestamp.xml#timestamp"/>,
|
|
<xref
|
|
href="impala_boolean.xml#boolean"/>
|
|
</p>
|
|
</dd>
|
|
|
|
</dlentry>
|
|
|
|
<dlentry id="cast_format">
|
|
|
|
<dt>
|
|
CAST(expression AS type FORMAT pattern)
|
|
</dt>
|
|
|
|
<dd>
|
|
<b>Purpose:</b> Returns <varname>expression</varname> converted to the
|
|
<varname>type</varname> data type based on the <varname>pattern</varname> format
|
|
string. This signature of <codeph>CAST()</codeph> with the <codeph>FORMAT</codeph>
|
|
clause is supported only for casts between <codeph>STRING</codeph> /
|
|
<codeph>CHAR</codeph> / <codeph>VARCHAR</codeph> types and <codeph>TIMESTAMP</codeph>
|
|
/ <codeph>DATE</codeph> types.
|
|
<note>
|
|
The patterns allowed in the <codeph>FORMAT</codeph> clause support ISO SQL:2016
|
|
standard patterns. Those patterns are not the same format patterns used with the
|
|
other Impala conversion functions, e.g. <codeph>TO_TIMESTAMP()</codeph> and
|
|
<codeph>FROM_TIMESTAMP()</codeph>.
|
|
</note>
|
|
|
|
<p>
|
|
The following rules apply to <varname>pattern</varname>. Any exceptions to these
|
|
rules are noted in the Details column of the table below.
|
|
<ul>
|
|
<li>
|
|
<varname>pattern</varname> is a case-insensitive <codeph>STRING</codeph> unless
|
|
noted otherwise in the table below.
|
|
</li>
|
|
|
|
<li>
|
|
If <varname>pattern</varname> is <codeph>NULL</codeph>, an empty string, or a
|
|
number, an error returns.
|
|
</li>
|
|
|
|
<li>
|
|
A fewer digits in <varname>expression</varname> than specified in the
|
|
<varname>pattern</varname> is accepted if a separator is correctly specified in
|
|
the <varname>pattern</varname>. For example, <codeph>CAST('5-01-2017' AS DATE
|
|
FORMAT 'MM-dd-yyyy')</codeph> returns <codeph>DATE'2017-05-01'</codeph>.
|
|
</li>
|
|
|
|
<li>
|
|
If fewer number of digits are in <varname>expression</varname> than specified in
|
|
the <varname>pattern</varname>, the current date is used to complete the year
|
|
pattern. For example, <codeph>CAST('19/05' AS DATE FORMAT 'YYYY/MM')</codeph>
|
|
will return <codeph>DATE'2019-05-01'</codeph> when executed on August 8, 2019.
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
<p>
|
|
The following format patterns are supported in the <codeph>FORMAT</codeph> clause.
|
|
<table frame="all" rowsep="1"
|
|
colsep="1" id="table_gbt_5ym_r3b">
|
|
<tgroup cols="3" align="left">
|
|
<colspec colname="c1" colnum="1" colwidth="1*"/>
|
|
<colspec colname="c2" colnum="2" colwidth="1.75*"/>
|
|
<colspec colname="newCol3" colnum="3" colwidth="6.6*"/>
|
|
<thead>
|
|
<row>
|
|
<entry>
|
|
Pattern
|
|
</entry>
|
|
<entry>
|
|
Description
|
|
</entry>
|
|
<entry>
|
|
Details
|
|
</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>
|
|
<codeph>YYYY</codeph>
|
|
</entry>
|
|
<entry>
|
|
4-digit year.
|
|
</entry>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>YYY</codeph>
|
|
</entry>
|
|
<entry>
|
|
Last 3 digits of a year.
|
|
</entry>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>YY</codeph>
|
|
</entry>
|
|
<entry>
|
|
Last 2 digits of a year.
|
|
</entry>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>Y</codeph>
|
|
</entry>
|
|
<entry>
|
|
Last digit of a year
|
|
</entry>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>RRRR</codeph>
|
|
</entry>
|
|
<entry>
|
|
4-digit round year
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
If 1,3 or 4-digit year values are provided in
|
|
<varname>expression</varname>, treated as <codeph>YYYY</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If 2-digit years are provided in <varname>expression</varname>, treated
|
|
as <codeph>RR</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
For date/time to string conversions, treated as <codeph>YYYY</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If <codeph>YYYY</codeph>, <codeph>YYY</codeph>, <codeph>YY</codeph>,
|
|
<codeph>Y</codeph>, or <codeph>RR</codeph> is given in the same
|
|
<varname>pattern</varname> for a string to date/time conversion, an
|
|
error returns.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>RR</codeph>
|
|
</entry>
|
|
<entry>
|
|
2-digit round year.
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
For date/time to string conversions, same as <codeph>YY</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
For string to date/time conversions, the first 2 digits of the year in
|
|
the return value depends on the specified two-digit year and the last
|
|
two digits of the current year as follows:
|
|
<ul>
|
|
<li>
|
|
<p>
|
|
If the specified 2-digit year is 00 to 49:
|
|
</p>
|
|
<ul>
|
|
<li>
|
|
<p>
|
|
If the last 2 digits of the current year are 00 to 49, the
|
|
returned year has the same first 2 digits as the current year.
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If the last 2 digits of the current year are 50 to 99, the
|
|
first 2 digits of the returned year are 1 greater than the
|
|
first 2 digits of the current year.
|
|
</p>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If the specified 2-digit year is 50 to 99:
|
|
</p>
|
|
<ul>
|
|
<li>
|
|
<p>
|
|
If the last 2 digits of the current year are 00 to 49, the
|
|
first 2 digits of the returned year are 1 less than the first
|
|
2 digits of the current year.
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If the last 2 digits of the current year are 50 to 99, the
|
|
returned year has the same first 2 digits as the current year.
|
|
</p>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If <codeph>YYYY</codeph>, <codeph>YYY</codeph>, <codeph>YY</codeph>,
|
|
<codeph>Y</codeph>, or <codeph>RR</codeph> is given in the same
|
|
<varname>pattern</varname> for a string to date/time conversion, an
|
|
error returns.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If 1-digit year values are provided in <varname>expression</varname>, it
|
|
is treated as <codeph>YYYY</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>Q</codeph>
|
|
</entry>
|
|
<entry>
|
|
Quarter of year (1-4)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Not supported in string to date/time conversions.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>MM</codeph>
|
|
</entry>
|
|
<entry>
|
|
Month number
|
|
</entry>
|
|
<entry>
|
|
<p> In date/time to string conversions, 1-digit months are
|
|
prefixed with a zero. </p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>MONTH</codeph>
|
|
|
|
<p>
|
|
<codeph>Month</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>month</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Full month name
|
|
</entry>
|
|
<entry>
|
|
In string to date/time conversions:
|
|
|
|
<ul>
|
|
<li> Converts a textual month name to a 2-digit month
|
|
number. </li>
|
|
|
|
<li>
|
|
The input strings are expected without trailing spaces, e.g.
|
|
"<codeph>June</codeph>", "<codeph>August</codeph>".
|
|
</li>
|
|
|
|
<li>
|
|
If the <codeph>FX</codeph> modifier is active for the token, a
|
|
9-character-long full month name with trailing spaces is expected for
|
|
the input string.
|
|
</li>
|
|
</ul>
|
|
|
|
<p>
|
|
In date/time to string conversions:
|
|
<ul>
|
|
<li>
|
|
Converts to a 9-character-long full month name with trailing spaces.
|
|
</li>
|
|
|
|
<li>
|
|
If the <codeph>FM</codeph> modifier is active for this token,
|
|
converts to a month name without trailing spaces.
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
This pattern token is case sensitive. <codeph>MONTH</codeph>,
|
|
<codeph>Month</codeph>, <codeph>month</codeph> would require different
|
|
casing of the input in string to date/time conversions and would produce
|
|
cased outputs in date/time to string conversions, For example,
|
|
<codeph>MONTH</codeph>, <codeph>Month</codeph>, <codeph>month</codeph>
|
|
would convert respectively <codeph>JULY</codeph>, <codeph>July</codeph>,
|
|
and <codeph>july</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>MON</codeph>
|
|
|
|
<p>
|
|
<codeph>Mon</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>mon</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Abbreviated 3-character month name
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
This pattern token is case sensitive. <codeph>MON</codeph>,
|
|
<codeph>Mon</codeph>, <codeph>mon</codeph> would require different
|
|
casing of the input in string to date/time conversions and would produce
|
|
cased outputs in date/time to string conversions, For example,
|
|
<codeph>MON</codeph>, <codeph>Mon</codeph>, <codeph>mon</codeph> would
|
|
convert respectively <codeph>JUL</codeph>, <codeph>Jul</codeph>, and
|
|
<codeph>jul</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>WW</codeph>
|
|
</entry>
|
|
<entry>
|
|
Week of year (1-53)
|
|
</entry>
|
|
<entry>
|
|
<p> Not supported in string to date/time conversions. </p>
|
|
|
|
|
|
|
|
<p> The 1st week begins on January 1st and ends on January
|
|
7th. </p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>W</codeph>
|
|
</entry>
|
|
<entry>
|
|
Week of month (1-5)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Not supported in string to date/time conversions.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
1st week begins on the 1st of the month and ends on the 7th.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>D</codeph>
|
|
</entry>
|
|
<entry>
|
|
Day of week (1-7)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Not supported in string to date/time conversions.
|
|
</p>
|
|
|
|
In date/time to string conversions, converts to a day number, for example,
|
|
1 for Sunday, 2 for Monday.
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>DD</codeph>
|
|
</entry>
|
|
<entry>
|
|
Day of month (1-31)
|
|
</entry>
|
|
<entry>
|
|
<p> In date/time to string conversions, 1-digit days are
|
|
prefixed with a zero. </p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>DDD</codeph>
|
|
</entry>
|
|
<entry>
|
|
Day of year (1-366)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In string to date/time conversions, providing <codeph>MM</codeph> and
|
|
<codeph>DD</codeph> along with <codeph>DDD</codeph> results an error,
|
|
e.g. <codeph>YYYY-MM-DDD</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>DAY</codeph>
|
|
|
|
<p>
|
|
<codeph>Day</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>day</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Day name
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Not supported in string to date/time conversions.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
In date/time to string conversions:
|
|
<ul>
|
|
<li>
|
|
Converts to a 9-character-long full day name with trailing spaces.
|
|
</li>
|
|
|
|
<li>
|
|
If the <codeph>FM</codeph> modifier is active for this token,
|
|
converts to a day name without trailing spaces.
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
This pattern token is case sensitive. <codeph>DAY</codeph>,
|
|
<codeph>Day</codeph>, <codeph>day</codeph> would produce cased outputs
|
|
in date/time to string conversions, For example, <codeph>DAY</codeph>,
|
|
<codeph>Day</codeph>, <codeph>day</codeph> would convert respectively
|
|
<codeph>MONDAY</codeph>, <codeph>Monday</codeph>, and
|
|
<codeph>monday</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>DY</codeph>
|
|
|
|
<p>
|
|
<codeph>Dy</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>dy</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Abbreviated 3-character day name
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Not supported in string to date/time conversions.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
This pattern token is case sensitive. <codeph>DY</codeph>,
|
|
<codeph>Dy</codeph>, <codeph>dy</codeph> would produce cased outputs in
|
|
date/time to string conversions, For example, <codeph>DY</codeph>,
|
|
<codeph>Dy</codeph>, <codeph>dy</codeph> would convert respectively
|
|
<codeph>MON</codeph>, <codeph>Mon</codeph>, and <codeph>mon</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>HH</codeph>
|
|
|
|
<p>
|
|
<codeph>HH12</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Hour of day (1-12)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In date/time to string conversions, 1-digit hours are prefixed with a
|
|
zero.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If provided hour in <varname>expression</varname> is not between 1 and
|
|
12, returns an error.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
If no AM/PM is provided in <varname>expression</varname>, the default is
|
|
<codeph>AM</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>HH24</codeph>
|
|
</entry>
|
|
<entry>
|
|
Hour of day (0-23)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In string to date/time conversions, if <codeph>HH12</codeph>,
|
|
<codeph>AM</codeph>, <codeph>PM</codeph> are given in the same
|
|
<varname>pattern</varname>, an error returns.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>MI</codeph>
|
|
</entry>
|
|
<entry>
|
|
Minute of hour (0-59)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In date/time to string conversions, 1-digit minutes are prefixed with a
|
|
zero.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>SS</codeph>
|
|
</entry>
|
|
<entry>
|
|
Second of minute (0-59)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In date/time to string conversions, 1-digit seconds are prefixed with a
|
|
zero.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>SSSSS</codeph>
|
|
</entry>
|
|
<entry>
|
|
Second of Day (0-86399)
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In string to timestamp conversions, if <codeph>SS</codeph>,
|
|
<codeph>HH</codeph>, <codeph>HH12</codeph>, <codeph>HH24</codeph>,
|
|
<codeph>MI</codeph>, <codeph>AM</codeph>/<codeph>PM</codeph> are given
|
|
in the same <varname>pattern</varname>, an error returns.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>FF</codeph>
|
|
|
|
<p>
|
|
<codeph>FF1</codeph>, ..., <codeph>FF9</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Fractional second
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
A number, 1 to 9, can be used to indicate the number of digits.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>FF</codeph> specifies a 9 digits fractional second.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>AM</codeph>
|
|
|
|
<p>
|
|
<codeph>PM</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>A.M.</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>P.M.</codeph>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Meridiem indicator
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
For date/time to string conversions, <codeph>AM</codeph> and
|
|
<codeph>PM</codeph> are treated as synonyms. For example, casting
|
|
<codeph>'2019-01-01 11:00 am'</codeph> to <codeph>TIMESTAMP</codeph>
|
|
with the <codeph>'YYYY-MM-DD HH12:MI PM'</codeph> pattern returns
|
|
<codeph>01-JAN-19 11.00.00.000000 AM</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
For string to date/time conversion, <codeph>HH24</codeph> in the same
|
|
<varname>pattern</varname> returns an error.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>TZH</codeph>
|
|
</entry>
|
|
<entry>
|
|
Timezone offset hour
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
An optional sign, + or -, and 2 digits for the value of signed numbers
|
|
are allowed for the source <varname>expression</varname>, e.g.
|
|
<codeph>+10</codeph>, <codeph>-05</codeph>, <codeph>04</codeph>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
The allowed values are from <codeph>-15</codeph> to <codeph>+5</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>TZM</codeph>
|
|
</entry>
|
|
<entry>
|
|
Timezone offset minute
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Unsigned numbers are allowed for the source
|
|
<varname>expression</varname>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
The allowed values are from <codeph>0</codeph> to <codeph>59</codeph>.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>-</codeph>
|
|
|
|
<p>
|
|
<codeph>.</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>/</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>,</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>'</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>;</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<codeph>:</codeph>
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
<space>
|
|
</p>
|
|
</entry>
|
|
<entry>
|
|
Separator
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
For string to date/time conversions, any separator character in the
|
|
<varname>pattern</varname> string would match any separator character in
|
|
the input <varname>expression</varname>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
For example, <codeph>CAST(“20191010” AS DATE FORMAT
|
|
“YYYY-MM-DD”)</codeph> returns an error, but <codeph>CAST("2019-.;10
|
|
10" AS DATE FORMAT "YYYY-MM-DD")</codeph> succeeds.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>T</codeph>
|
|
</entry>
|
|
<entry>
|
|
Separates the date from the time.
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
This pattern is used for accepting ISO 8601 date/time formats.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
Example: <codeph>YYYY-MM-DD<b>T</b>HH24:MI:SS.FF9Z</codeph>
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>Z</codeph>
|
|
</entry>
|
|
<entry>
|
|
Indicates the zero hour offset from UTC.
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
This pattern is used for accepting ISO 8601 date/time formats.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>FX</codeph>
|
|
</entry>
|
|
<entry>
|
|
Forces an exact match between the format pattern,
|
|
<varname>pattern</varname>, and the input argument,
|
|
<varname>expression</varname>.
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
Must be specified at the beginning of the format
|
|
<varname>pattern</varname> and is valid for the whole
|
|
<varname>pattern</varname>.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
In string to date/time conversions:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>
|
|
Forces strict separator matching, including the separator character.
|
|
</li>
|
|
|
|
<li>
|
|
Expects all the tokens to have the maximum possible length.
|
|
</li>
|
|
</ul>
|
|
|
|
<p>
|
|
In date/time to string conversions, the outputs are padded as follows:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>
|
|
Numeric outputs are left padded with zeros.
|
|
</li>
|
|
|
|
<li>
|
|
Text outputs are right padded with spaces.
|
|
</li>
|
|
</ul>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeph>FM</codeph>
|
|
</entry>
|
|
<entry>
|
|
Overrides <codeph>FX</codeph>.
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
In a date/time to string conversions, <codeph>FM</codeph> suppresses
|
|
blank padding for the element immediately following the
|
|
<codeph>FM</codeph> in the <varname>pattern</varname> string, e.g.
|
|
"<codeph>2010-1-9</codeph>".
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
In string to date/time conversions, <codeph>FM</codeph> is used to
|
|
override the effect of <codeph>FX</codeph> for certain tokens as
|
|
follows:
|
|
<ul>
|
|
<li>
|
|
<p>
|
|
The length of the token in the input argument can be shorter than
|
|
the max length of that token type if followed by a separator, e.g.
|
|
1-digit month, less than 4-digit year.
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
<codeph>FM</codeph> modifier skips the separators and affects the
|
|
next non-separator token. For example, <codeph>CAST('1999-10-2' AS
|
|
TIMESTAMP FORMAT 'FXYYYY-MM<b>FM</b>-DD') </codeph>returns
|
|
<codeph>1999-10-02 00:00:00</codeph> as <codeph>FM</codeph> is
|
|
applied to <codeph>DD</codeph> and not to the
|
|
separator(<codeph>-</codeph>).
|
|
</p>
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
Free text
|
|
</entry>
|
|
<entry>
|
|
Nested string
|
|
</entry>
|
|
<entry>
|
|
<p>
|
|
You can specify a free text with surrounding double quotes (") in
|
|
<varname>pattern</varname> where the same text is expected in the input
|
|
argument without surrounding double quotes.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
In date/time to string conversions, the string is included in the output
|
|
with the characters' case preserved.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
In string to date/time conversions, the nested string is not included in
|
|
the resulting date/time object. However, the nested string has to match
|
|
the related part of the input string, including the case.
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
The following rules apply:
|
|
<ul>
|
|
<li>
|
|
<p>
|
|
If the <varname>pattern</varname> is surrounded by double quotes,
|
|
double quotes surrounding the free text token must be escaped with
|
|
a single backslash (<codeph>\"</codeph>).
|
|
</p>
|
|
|
|
<p>
|
|
For example: <codeph>CAST('"Date:"2019-11-10' AS DATE FORMAT
|
|
"<b>\"Date:\"</b>YYYY-MM-DD")</codeph>
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If the <varname>pattern</varname> is surrounded by double quotes,
|
|
and there is an escaped double quotes inside a text token that is
|
|
itself surrounded by escaped double quotes, escape the double
|
|
quotes in the free text token with a triple backslash:
|
|
(<codeph>\\\"</codeph>)
|
|
</p>
|
|
|
|
<p>
|
|
For example: <codeph>CAST("1985 some \"text 11-28" AS DATE'''
|
|
FORMAT "YYYY<b>\" some \\\"text \"</b>MM-DD")</codeph>
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If the <varname>pattern</varname> is surrounded by single quotes,
|
|
the free text token can be surrounded by (non-escaped) double
|
|
quotes. To include double quotes within the free text token, those
|
|
double quotes must be escaped by a single backslash.
|
|
</p>
|
|
|
|
<p>
|
|
For example: <codeph>CAST('"Date:"2019-11-10' AS DATE FORMAT
|
|
'"<b>\"Date:\"</b>"YYYY-MM-DD')</codeph>
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
Literal single quotes/apostrophes (<codeph>'</codeph>) in the
|
|
nested string must be escaped with a single backslash if the whole
|
|
pattern string is delimited by single quotes.
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>
|
|
If a free text token contains any separator characters in the
|
|
beginning, and the text token is right after a separator token
|
|
sequence, an error returns as it's not trivial to find where the
|
|
separator sequence ends and where the free text starts. In this
|
|
case, use <codeph>FX</codeph> for strict matching.
|
|
</p>
|
|
|
|
<p>
|
|
For example: <codeph>CAST("1985-11- ' 10" AS DATE FORMAT
|
|
"YYYY-MM-<b>\" ' \"</b>DD")</codeph> returns an error, but
|
|
removing the dash before the text token makes this succeed.
|
|
</p>
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
</p>
|
|
|
|
<p>
|
|
<b>Examples:</b>
|
|
</p>
|
|
<table frame="all" rowsep="1" colsep="1" id="table_qqg_txn_r3b">
|
|
<tgroup cols="2" align="left">
|
|
<colspec colname="c1" colnum="1" colwidth="1*"/>
|
|
<colspec colname="c2" colnum="2" colwidth="1*"/>
|
|
<thead>
|
|
<row>
|
|
<entry>
|
|
Input
|
|
</entry>
|
|
<entry>
|
|
Output
|
|
</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST("02-11-2014" AS DATE FORMAT 'dd-mm-yyyy')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2014-11-02
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST("365 2014" AS DATE FORMAT 'DDD-YYYY')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2014-12-31
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST("5-01-26" AS DATE FORMAT 'YY-MM-DD')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
Executed at 2019-01-01 11:11:11:
|
|
|
|
<p>
|
|
2015-01-26
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2018-11-10T15:11:04Z' AS TIMESTAMP
|
|
FORMAT 'YYYY-MM-DDTHH24:MI:SSZ')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2018-11-10 15:11:04
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST("95-01-28" AS DATE
|
|
FORMAT 'YYY-MM-DD')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
Executed at 2019-01-01 11:11:11:
|
|
|
|
<p>
|
|
2095-01-28
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST("49-01-15" AS DATE
|
|
FORMAT 'RR-MM-DD')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
Round year when last 2 digits of current year is greater than 49.
|
|
|
|
<p>
|
|
Executed at 2099-01-01 11:11:11:
|
|
</p>
|
|
|
|
|
|
|
|
<p>
|
|
2149-01-15
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2019.10.10 13:30:40.123456 +01:30'
|
|
AS TIMESTAMP
|
|
FORMAT 'YYYY-MM-DD HH24:MI:SS.FF9 TZH:TZM') </codeblock>
|
|
</entry>
|
|
<entry>
|
|
2019-10-10 13:30:40.123456000
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2001-03-01 03:10:15.123456 -01:30'
|
|
AS TIMESTAMP
|
|
FORMAT 'FXYYYY-MM-DD HH12:MI:SS.FF6 TZH:TZM')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2001-03-01 03:10:15.123456000
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2001-03-02 03:10:15'
|
|
AS TIMESTAMP
|
|
FORMAT 'FXYYYY MM-DD HH12:MI:SS')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
NULL because the separator between the year and month do not match.
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2001-3-05'
|
|
AS TIMESTAMP
|
|
FORMAT 'FXYYYY-MM-DD')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
NULL because the length of the month token does not match the
|
|
<varname>pattern</varname>.
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2001-3-11 3:15:00.12345'
|
|
AS TIMESTAMP
|
|
FORMAT 'FXYYYY-FMMM-DD FMHH12:MI:SS.FMFF')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2001-03-11 03:15:00.123450000
|
|
|
|
<p>
|
|
The multiple <codeph>FM</codeph> modifiers for the month and hour override
|
|
the <codeph>FX</codeph> and suppress padding.
|
|
</p>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('2019-01-01 01:01:01'
|
|
AS TIMESTAMP
|
|
FORMAT 'FMHH12:MI:FMSS')</codeblock>
|
|
</entry>
|
|
<entry>
|
|
1:01:1
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<codeblock>CAST('Date: 2019-11-10'
|
|
AS DATE
|
|
FORMAT '"Date: "YYYY-MM-DD')
|
|
</codeblock>
|
|
</entry>
|
|
<entry>
|
|
2019-11-10
|
|
</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
</dd>
|
|
|
|
</dlentry>
|
|
|
|
<dlentry rev="2.3.0" id="typeof">
|
|
|
|
<dt>
|
|
TYPEOF(expression)
|
|
</dt>
|
|
|
|
<dd>
|
|
<b>Purpose:</b> Returns the name of the data type corresponding to
|
|
<varname>expression</varname>. For types with extra attributes, such as length for
|
|
<codeph>CHAR</codeph> and <codeph>VARCHAR</codeph>, or precision and scale for
|
|
<codeph>DECIMAL</codeph>, includes the full specification of the type.
|
|
<p>
|
|
<b>Return type:</b> <codeph>STRING</codeph>
|
|
</p>
|
|
|
|
<p>
|
|
<b>Usage notes:</b> Typically used in interactive exploration of a schema, or in
|
|
application code that programmatically generates schema definitions such as
|
|
<codeph>CREATE TABLE</codeph> statements, for example, to get the type of an
|
|
expression such as <codeph>col1 / col2</codeph> or <codeph>CONCAT(col1, col2,
|
|
col3)</codeph>. This function is especially useful for arithmetic expressions
|
|
involving <codeph>DECIMAL</codeph> types because the precision and scale of the
|
|
result is can be different than that of the operands.
|
|
</p>
|
|
|
|
<p
|
|
conref="../shared/impala_common.xml#common/example_blurb"
|
|
/>
|
|
|
|
<p>
|
|
<codeph>TYPEOF(2)</codeph> returns <codeph>TINYINT</codeph>.
|
|
</p>
|
|
|
|
<p>
|
|
<codeph>TYPEOF(NOW())</codeph> returns <codeph>TIMESTAMP</codeph>.
|
|
</p>
|
|
</dd>
|
|
|
|
</dlentry>
|
|
</dl>
|
|
|
|
</conbody>
|
|
|
|
</concept>
|