select count(*) from where c01d27 IN ('2', '8')select count(*) from where c01d27='2' or c01d27='8'
SQL> select count(*) from c01d where c01d27='2' or c01d27='8';
Executed in 0.531 seconds
Executed in 0.515 seconds
Executed in 0.515 seconds
SQL> select count(*) from c01d where c01d27 IN ('2', '8');
Executed in 0.547 seconds
Executed in 0.516 seconds
Executed in 0.547 seconds能看出来好一点...select count(*) from where c01d26 NOT IN ('2025', '2027', '2029') ;下周接着测下班了。....
SQL> select count(*) from c01d where c01d27='2' or c01d27='8';
Executed in 0.531 seconds
Executed in 0.515 seconds
Executed in 0.515 seconds
SQL> select count(*) from c01d where c01d27 IN ('2', '8');
Executed in 0.547 seconds
Executed in 0.516 seconds
Executed in 0.547 seconds能看出来好一点...select count(*) from where c01d26 NOT IN ('2025', '2027', '2029') ;下周接着测下班了。....
not in (NULL) 为true
not exists(NULL) 为false
select count(*) from where c01d27='2'
unoin all
select count(*) from where c01d27='8'