# # Init section # --disable_warnings drop table if exists t1; --enable_warnings # # Simple IF tests # select IF(0,"ERROR","this"),IF(1,"is","ERROR"),IF(NULL,"ERROR","a"),IF(1,2,3)|0,IF(1,2.0,3.0)+0 ; # # Test of IF and case-sensitiveness # CREATE TABLE t1 (st varchar(255) NOT NULL, u int(11) NOT NULL) TYPE=MyISAM; INSERT INTO t1 VALUES ('a',1),('A',1),('aa',1),('AA',1),('a',1),('aaa',0),('BBB',0); select if(1,st,st) s from t1 order by s; select if(u=1,st,st) s from t1 order by s; select if(u=1,binary st,st) s from t1 order by s; select if(u=1,st,binary st) s from t1 where st like "%a%" order by s; drop table t1; # # Problem with IF() # create table t1 (num double(12,2)); insert into t1 values (144.54); select sum(if(num is null,0.00,num)) from t1; drop table t1; create table t1 (x int, y int); insert into t1 values (0,6),(10,16),(20,26),(30,10),(40,46),(50,56); select min(if(y -x > 5,y,NULL)), max(if(y - x > 5,y,NULL)) from t1; drop table t1;