mariadb/mysql-test/t/case.test

#
# Testing of CASE
#

--disable_warnings
drop table if exists t1;
--enable_warnings

select CASE "b" when "a" then 1 when "b" then 2 END;
select CASE "c" when "a" then 1 when "b" then 2 END;
select CASE "c" when "a" then 1 when "b" then 2 ELSE 3 END;
select CASE BINARY "b" when "a" then 1 when "B" then 2 WHEN "b" then "ok" END;
select CASE "b" when "a" then 1 when binary "B" then 2 WHEN "b" then "ok" END;
select CASE concat("a","b") when concat("ab","") then "a" when "b" then "b" end;
select CASE when 1=0 then "true" else "false" END;
select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
explain extended select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
select CASE 2.0 when 1 then "one" WHEN 2.0 then "two" ELSE "more" END;
select (CASE "two" when "one" then "1" WHEN "two" then "2" END) | 0;
select (CASE "two" when "one" then 1.00 WHEN "two" then 2.00 END) +0.0;
select case 1/0 when "a" then "true" else "false" END;
select case 1/0 when "a" then "true" END;
select (case 1/0 when "a" then "true" END) | 0;
select (case 1/0 when "a" then "true" END) + 0.0;
select case when 1>0 then "TRUE" else "FALSE" END;
select case when 1<0 then "TRUE" else "FALSE" END;

#
# Test bug when using GROUP BY on CASE
#
create table t1 (a int);
insert into t1 values(1),(2),(3),(4);
select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
explain extended select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
select case a when 1 then "one" when 2 then "two" else "nothing" end as fcase, count(*) from t1 group by fcase;
drop table t1;

#
# Test MAX(CASE ... ) that can return null
#

create table t1 (row int not null, col int not null, val varchar(255) not null);
insert into t1 values (1,1,'orange'),(1,2,'large'),(2,1,'yellow'),(2,2,'medium'),(3,1,'green'),(3,2,'small');
select max(case col when 1 then val else null end) as color from t1 group by row;
drop table t1;

SET NAMES latin1;

#
# CASE and argument types/collations aggregation into result 
#
CREATE TABLE t1 SELECT 
 CASE WHEN 1 THEN _latin1'a' COLLATE latin1_danish_ci ELSE _latin1'a' END AS c1,
 CASE WHEN 1 THEN _latin1'a' ELSE _latin1'a' COLLATE latin1_danish_ci END AS c2,
 CASE WHEN 1 THEN 'a' ELSE  1  END AS c3,
 CASE WHEN 1 THEN  1  ELSE 'a' END AS c4,
 CASE WHEN 1 THEN 'a' ELSE 1.0 END AS c5,
 CASE WHEN 1 THEN 1.0 ELSE 'a' END AS c6,
 CASE WHEN 1 THEN  1  ELSE 1.0 END AS c7,
 CASE WHEN 1 THEN 1.0 ELSE  1  END AS c8
;
SHOW CREATE TABLE t1;
DROP TABLE t1;

--error 1266
SELECT CASE 
  WHEN 1 
  THEN _latin1'a' COLLATE latin1_danish_ci 
  ELSE _latin1'a' COLLATE latin1_swedish_ci
  END;

--error 1269
SELECT CASE _latin1'a' COLLATE latin1_general_ci
  WHEN _latin1'a' COLLATE latin1_danish_ci  THEN 1
  WHEN _latin1'a' COLLATE latin1_swedish_ci THEN 2
  END;

SELECT 
CASE _latin1'a' COLLATE latin1_general_ci  WHEN _latin1'A' THEN '1' ELSE 2 END,
CASE _latin1'a' COLLATE latin1_bin         WHEN _latin1'A' THEN '1' ELSE 2 END,
CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_swedish_ci THEN '1' ELSE 2 END,
CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_bin        THEN '1' ELSE 2 END
;

#
# COALESCE is a CASE abbrevation:
#
# COALESCE(v1,v2) == CASE WHEN v1 IS NOT NULL THEN v1 ELSE v2 END
#
# COALESCE(V1, V2, . . . ,Vn ) =  
#     CASE WHEN V1 IS NOT NULL THEN V1 ELSE COALESCE (V2, . . . ,Vn) END
#
# Check COALESCE argument types aggregation

--error 1266
CREATE TABLE t1 SELECT COALESCE(_latin1'a',_latin2'a');
--error 1266
CREATE TABLE t1 SELECT COALESCE('a' COLLATE latin1_swedish_ci,'b' COLLATE latin1_bin);
CREATE TABLE t1 SELECT 
 COALESCE(1), COALESCE(1.0),COALESCE('a'),
 COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
 COALESCE('a' COLLATE latin1_bin,'b');
explain extended SELECT 
 COALESCE(1), COALESCE(1.0),COALESCE('a'),
 COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
 COALESCE('a' COLLATE latin1_bin,'b');
SHOW CREATE TABLE t1;
DROP TABLE t1;