4.9 KiB
title, language
| title | language |
|---|---|
| GROUP BY | en |
GROUP BY
description
GROUP BY GROUPING SETS ｜ CUBE ｜ ROLLUP is an extension to GROUP BY clause. This syntax lets you define multiple groupings in the same query. GROUPING SETS produce a single result set that is equivalent to a UNION ALL of differently grouped rows
For example GROUPING SETS clause:
SELECT a, b, SUM( c ) FROM tab1 GROUP BY GROUPING SETS ( (a, b), (a), (b), ( ) );
This statement is equivalent to:
SELECT a, b, SUM( c ) FROM tab1 GROUP BY a, b
UNION
SELECT a, null, SUM( c ) FROM tab1 GROUP BY a
UNION
SELECT null, b, SUM( c ) FROM tab1 GROUP BY b
UNION
SELECT null, null, SUM( c ) FROM tab1
GROUPING(expr) indicates whether a specified column expression in a GROUP BY list is aggregated or not. GROUPING returns 1 for aggregated or 0 for not aggregated in the result set.
GROUPING_ID(expr [ , expr [ , ... ] ]) describes which of a list of expressions are grouped in a row produced by a GROUP BY query. The GROUPING_ID function simply returns the decimal equivalent of the binary value formed as a result of the concatenation of the values returned by the GROUPING functions.
Syntax
SELECT ...
FROM ...
[ ... ]
GROUP BY [
, ... |
GROUPING SETS [, ...] ( groupSet [ , groupSet [ , ... ] ] ) |
ROLLUP(expr [ , expr [ , ... ] ]) |
expr [ , expr [ , ... ] ] WITH ROLLUP |
CUBE(expr [ , expr [ , ... ] ]) |
expr [ , expr [ , ... ] ] WITH CUBE
]
[ ... ]
Parameters
groupSet is a set of expression or column or it's alias appearing in the query block’s SELECT list. groupSet ::= { ( expr [ , expr [ , ... ] ] )}
expr is expression or column or it's alias appearing in the query block’s SELECT list.
Note
doris supports PostgreSQL like syntax, for example:
SELECT a, b, SUM( c ) FROM tab1 GROUP BY GROUPING SETS ( (a, b), (a), (b), ( ) );
SELECT a, b,c, SUM( d ) FROM tab1 GROUP BY ROLLUP(a,b,c)
SELECT a, b,c, SUM( d ) FROM tab1 GROUP BY CUBE(a,b,c)
ROLLUP(a,b,c) is equivalent to GROUPING SETS as follows:
GROUPING SETS (
(a,b,c),
( a, b ),
( a),
( )
)
CUBE ( a, b, c ) is equivalent to GROUPING SETS as follows:
GROUPING SETS (
( a, b, c ),
( a, b ),
( a, c ),
( a ),
( b, c ),
( b ),
( c ),
( )
)
example
This is a simple example
> SELECT * FROM t;
+------+------+------+
| k1 | k2 | k3 |
+------+------+------+
| a | A | 1 |
| a | A | 2 |
| a | B | 1 |
| a | B | 3 |
| b | A | 1 |
| b | A | 4 |
| b | B | 1 |
| b | B | 5 |
+------+------+------+
8 rows in set (0.01 sec)
> SELECT k1, k2, SUM(k3) FROM t GROUP BY GROUPING SETS ( (k1, k2), (k2), (k1), ( ) );
+------+------+-----------+
| k1 | k2 | sum(`k3`) |
+------+------+-----------+
| b | B | 6 |
| a | B | 4 |
| a | A | 3 |
| b | A | 5 |
| NULL | B | 10 |
| NULL | A | 8 |
| a | NULL | 7 |
| b | NULL | 11 |
| NULL | NULL | 18 |
+------+------+-----------+
9 rows in set (0.06 sec)
> SELECT k1, k2, GROUPING_ID(k1,k2), SUM(k3) FROM t GROUP BY GROUPING SETS ((k1, k2), (k1), (k2), ());
+------+------+---------------+----------------+
| k1 | k2 | grouping_id(k1,k2) | sum(`k3`) |
+------+------+---------------+----------------+
| a | A | 0 | 3 |
| a | B | 0 | 4 |
| a | NULL | 1 | 7 |
| b | A | 0 | 5 |
| b | B | 0 | 6 |
| b | NULL | 1 | 11 |
| NULL | A | 2 | 8 |
| NULL | B | 2 | 10 |
| NULL | NULL | 3 | 18 |
+------+------+---------------+----------------+
9 rows in set (0.02 sec)
keyword
GROUP, GROUPING, GROUPING_ID, GROUPING_SETS, GROUPING SETS, CUBE, ROLLUP