create table r_test
(
a int,
b varchar(255)
)
insert r_test values(0, null)
insert r_test values(1, 'abcd')
select a, CASE WHEN b is null THEN '' ELSE b END as b from r_test
查询结果
0 ''
1 'abcd'
(
a int,
b varchar(255)
)
insert r_test values(0, null)
insert r_test values(1, 'abcd')
select a, CASE WHEN b is null THEN '' ELSE b END as b from r_test
查询结果
0 ''
1 'abcd'