Question

如何从表中选择所有记录，但col-B中值为-43的空值除外？

COLUMN-A COLUMN-B
--------------------
N       433
N       431
Y       431
        431
        431
Y       431
N       431
N       520
        520
N       304
        390
N       410
        433

期望的输出：

COLUMN-A COLUMN-B 
-------------------- 
N        433 
N        431 
Y        431 
Y        431 
N        431 
N        520 
         520 
N        304 
         390        
N        410 
         433

Answer 1

(select * from table where column_b ! - 431 )
union 
(select * from table where column_b = 431 and column_a is not null);

Answer 2

你可以写：

SELECT *
FROM table
WHERE column_b <> 431
OR    column_a IS NOT NULL;

Answer 3

试试这个： -

Select * from 
(select * from table where column_b = 431 and column_a is not null
 union all
 select * from table where column_b <> 431) A

避免特定记录的空值

3 个答案: