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				https://github.com/MariaDB/server.git
				synced 2025-11-04 04:46:15 +01:00 
			
		
		
		
	
		
			
				
	
	
		
			94 lines
		
	
	
	
		
			3.1 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
			
		
		
	
	
			94 lines
		
	
	
	
		
			3.1 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
flush status;
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	0
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create table t2 (sal int(10));
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create table t3 (sal int(10),id int);
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insert into t3 values (0,1),(1,2),(2,3),(3,4);
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create aggregate function f1(x INT) returns int
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begin
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declare tot_sum int default 0;
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declare continue handler for not found return tot_sum;
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loop
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fetch group next row;
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set tot_sum= tot_sum + x;
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end loop;
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end|
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create aggregate function f2 (x int) returns int
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begin
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declare counter int default 0;
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declare continue handler for not found return 0;
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loop
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fetch group next row;
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set counter =counter + (select f1(sal) from t1); 
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end loop;
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end|
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create table t1 (sal int(10),id int(10));
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INSERT INTO t1 (sal,id) VALUES (5000,1);
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INSERT INTO t1 (sal,id) VALUES (2000,2);
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INSERT INTO t1 (sal,id) VALUES (1000,3);
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Normal select with custom aggregate function
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select f1(sal) from t1 where id>= 1;
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f1(sal)
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8000
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	1
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subqueries with custom aggregates
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explain
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select * from t1, (select f1(sal) as a  from t1 where id>= 1) q where q.a=t1.sal;
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id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
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1	PRIMARY	<derived2>	ref	key0	key0	5	test.t1.sal	2	
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2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	2
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explain
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select * from t1, (select sal as a from t1 where (select f1(t3.sal) from t3) >=-1 ) q where q.a=t1.sal;
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id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
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1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
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3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	3
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explain
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select (select f1(sal) as a from t3 where t3.id= t1.id )  from t1 ;
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id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
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2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	Using where
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	4
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explain
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select (select f1(sal) as a from t3 where t3.id= t1.id )  from t1 ;
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id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
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2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	Using where
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	5
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custom aggregates inside other customm aggregates
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explain
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select f2(sal) from t1;
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id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	6
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cte with custom aggregates
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with agg_sum as (
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select f1(sal) from t1 where t1.id >=1 group by t1.id
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)
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select * from agg_sum;
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f1(sal)
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5000
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2000
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1000
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show  status like "%custom_aggregate%";
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Variable_name	Value
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Feature_custom_aggregate_functions	7
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drop table t2,t1,t3;
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drop function f1;
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drop function f2;
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