layout | title | displayTitle | license |
---|---|---|---|
global |
Literals |
Literals |
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.
|
A literal (also known as a constant) represents a fixed data value. Spark SQL supports the following literals:
- String Literal
- Binary Literal
- Null Literal
- Boolean Literal
- Numeric Literal
- Datetime Literal
- Interval Literal
A string literal is used to specify a character string value.
'char [ ... ]' | "char [ ... ]"
-
char
One character from the character set. Use
\
to escape special characters (e.g.,'
or\
).
SELECT 'Hello, World!' AS col;
+-------------+
| col|
+-------------+
|Hello, World!|
+-------------+
SELECT "SPARK SQL" AS col;
+---------+
| col|
+---------+
|Spark SQL|
+---------+
SELECT 'it\'s $10.' AS col;
+---------+
| col|
+---------+
|It's $10.|
+---------+
A binary literal is used to specify a byte sequence value.
X { 'num [ ... ]' | "num [ ... ]" }
-
num
Any hexadecimal number from 0 to F.
SELECT X'123456' AS col;
+----------+
| col|
+----------+
|[12 34 56]|
+----------+
A null literal is used to specify a null value.
NULL
SELECT NULL AS col;
+----+
| col|
+----+
|NULL|
+----+
A boolean literal is used to specify a boolean value.
TRUE | FALSE
SELECT TRUE AS col;
+----+
| col|
+----+
|true|
+----+
A numeric literal is used to specify a fixed or floating-point number.
[ + | - ] digit [ ... ] [ L | S | Y ]
-
digit
Any numeral from 0 to 9.
-
L
Case insensitive, indicates
BIGINT
, which is an 8-byte signed integer number. -
S
Case insensitive, indicates
SMALLINT
, which is a 2-byte signed integer number. -
Y
Case insensitive, indicates
TINYINT
, which is a 1-byte signed integer number. -
default (no postfix)
Indicates a 4-byte signed integer number.
SELECT -2147483648 AS col;
+-----------+
| col|
+-----------+
|-2147483648|
+-----------+
SELECT 9223372036854775807l AS col;
+-------------------+
| col|
+-------------------+
|9223372036854775807|
+-------------------+
SELECT -32Y AS col;
+---+
|col|
+---+
|-32|
+---+
SELECT 482S AS col;
+---+
|col|
+---+
|482|
+---+
decimal literals:
decimal_digits { [ BD ] | [ exponent BD ] } | digit [ ... ] [ exponent ] BD
double literals:
decimal_digits { D | exponent [ D ] } | digit [ ... ] { exponent [ D ] | [ exponent ] D }
While decimal_digits is defined as
[ + | - ] { digit [ ... ] . [ digit [ ... ] ] | . digit [ ... ] }
and exponent is defined as
E [ + | - ] digit [ ... ]
-
digit
Any numeral from 0 to 9.
-
D
Case insensitive, indicates
DOUBLE
, which is an 8-byte double-precision floating point number. -
BD
Case insensitive, indicates
DECIMAL
, with the total number of digits as precision and the number of digits to right of decimal point as scale.
SELECT 12.578 AS col;
+------+
| col|
+------+
|12.578|
+------+
SELECT -0.1234567 AS col;
+----------+
| col|
+----------+
|-0.1234567|
+----------+
SELECT -.1234567 AS col;
+----------+
| col|
+----------+
|-0.1234567|
+----------+
SELECT 123. AS col;
+---+
|col|
+---+
|123|
+---+
SELECT 123.BD AS col;
+---+
|col|
+---+
|123|
+---+
SELECT 5E2 AS col;
+-----+
| col|
+-----+
|500.0|
+-----+
SELECT 5D AS col;
+---+
|col|
+---+
|5.0|
+---+
SELECT -5BD AS col;
+---+
|col|
+---+
| -5|
+---+
SELECT 12.578e-2d AS col;
+-------+
| col|
+-------+
|0.12578|
+-------+
SELECT -.1234567E+2BD AS col;
+---------+
| col|
+---------+
|-12.34567|
+---------+
SELECT +3.e+3 AS col;
+------+
| col|
+------+
|3000.0|
+------+
SELECT -3.E-3D AS col;
+------+
| col|
+------+
|-0.003|
+------+
A Datetime literal is used to specify a datetime value.
DATE { 'yyyy' |
'yyyy-[m]m' |
'yyyy-[m]m-[d]d' |
'yyyy-[m]m-[d]d[T]' }
Note: defaults to 01
if month or day is not specified.
SELECT DATE '1997' AS col;
+----------+
| col|
+----------+
|1997-01-01|
+----------+
SELECT DATE '1997-01' AS col;
+----------+
| col|
+----------+
|1997-01-01|
+----------+
SELECT DATE '2011-11-11' AS col;
+----------+
| col|
+----------+
|2011-11-11|
+----------+
TIMESTAMP { 'yyyy' |
'yyyy-[m]m' |
'yyyy-[m]m-[d]d' |
'yyyy-[m]m-[d]d ' |
'yyyy-[m]m-[d]d[T][h]h[:]' |
'yyyy-[m]m-[d]d[T][h]h:[m]m[:]' |
'yyyy-[m]m-[d]d[T][h]h:[m]m:[s]s[.]' |
'yyyy-[m]m-[d]d[T][h]h:[m]m:[s]s.[ms][ms][ms][us][us][us][zone_id]'}
Note: defaults to 00
if hour, minute or second is not specified.
zone_id
should have one of the forms:
- Z - Zulu time zone UTC+0
+|-[h]h:[m]m
- An id with one of the prefixes UTC+, UTC-, GMT+, GMT-, UT+ or UT-, and a suffix in the formats:
+|-h[h]
+|-hh[:]mm
+|-hh:mm:ss
+|-hhmmss
- Region-based zone IDs in the form
area/city
, such asEurope/Paris
Note: defaults to the session local timezone (set via spark.sql.session.timeZone
) if zone_id
is not specified.
SELECT TIMESTAMP '1997-01-31 09:26:56.123' AS col;
+-----------------------+
| col|
+-----------------------+
|1997-01-31 09:26:56.123|
+-----------------------+
SELECT TIMESTAMP '1997-01-31 09:26:56.66666666UTC+08:00' AS col;
+--------------------------+
| col |
+--------------------------+
|1997-01-30 17:26:56.666666|
+--------------------------+
SELECT TIMESTAMP '1997-01' AS col;
+-------------------+
| col|
+-------------------+
|1997-01-01 00:00:00|
+-------------------+
An interval literal is used to specify a fixed period of time.
INTERVAL interval_value interval_unit [ interval_value interval_unit ... ] |
INTERVAL 'interval_value interval_unit [ interval_value interval_unit ... ]' |
INTERVAL interval_string_value interval_unit TO interval_unit
-
interval_value
Syntax:
[ + | - ] number_value | '[ + | - ] number_value'
-
interval_string_value
year-month/day-time interval string.
-
interval_unit
Syntax:
YEAR[S] | MONTH[S] | WEEK[S] | DAY[S] | HOUR[S] | MINUTE[S] | SECOND[S] | MILLISECOND[S] | MICROSECOND[S]
SELECT INTERVAL 3 YEAR AS col;
+-------+
| col|
+-------+
|3 years|
+-------+
SELECT INTERVAL -2 HOUR '3' MINUTE AS col;
+--------------------+
| col|
+--------------------+
|-1 hours -57 minutes|
+--------------------+
SELECT INTERVAL '1 YEAR 2 DAYS 3 HOURS';
+----------------------+
| col|
+----------------------+
|1 years 2 days 3 hours|
+----------------------+
SELECT INTERVAL 1 YEARS 2 MONTH 3 WEEK 4 DAYS 5 HOUR 6 MINUTES 7 SECOND 8
MILLISECOND 9 MICROSECONDS AS col;
+-----------------------------------------------------------+
| col|
+-----------------------------------------------------------+
|1 years 2 months 25 days 5 hours 6 minutes 7.008009 seconds|
+-----------------------------------------------------------+
SELECT INTERVAL '2-3' YEAR TO MONTH AS col;
+----------------+
| col|
+----------------+
|2 years 3 months|
+----------------+
SELECT INTERVAL '20 15:40:32.99899999' DAY TO SECOND AS col;
+---------------------------------------------+
| col|
+---------------------------------------------+
|20 days 15 hours 40 minutes 32.998999 seconds|
+---------------------------------------------+