Question

说我有一张桌子

SELECT * INTO MyTable FROM (
  VALUES ('col1_a', 'col2_a', 'col3_a', 'coln_a'),
         ('col1_b', 'col2_b', 'col3_b', 'coln_b'),
         ('col1_c', 'col2_c', 'col3_c', 'coln_c')
) t (col1, col2, col3, coln)

我只想删除与我特定的每个列值匹配的行（考虑行非常相似，只有一两列不同）

当然我可以写

DELETE MyTable WHERE col1='col1_a' AND col2='col2_a' AND col3='col3_a' AND coln='coln_a'
DELETE MyTable WHERE col1='col1_b' AND col2='col2_b' AND col3='col3_b' AND coln='coln_b'

但那太烦人了。我想知道是否可以通过简单地列出值来方便地编写它？我试过这个

DELETE MyTable FROM (
  VALUES ('col1_a', 'col2_a', 'col3_a', 'coln_a'),
         ('col1_b', 'col2_b', 'col3_b', 'coln_b')
) t (col1, col2, col3, coln)

但是刚刚删除了MyTable中的所有行，请提供帮助。

Answer 1

您可以在INNER JOIN声明中使用DELETE：

DELETE t1
FROM MyTable t1
INNER JOIN (
    SELECT *
    FROM (VALUES 
        ('col1_a', 'col2_a', 'col3_a', 'coln_a'),
        ('col1_b', 'col2_b', 'col3_b', 'coln_b')
    )AS a(col1, col2, col3, coln)
) t2
    ON t2.col1 = t1.col1
    AND t2.col2 = t1.col2
    AND t2.col3 = t1.col3

如Frisbee所述，您可以删除SELECT *：

DELETE t1
FROM MyTable t1
INNER JOIN (
    VALUES 
        ('col1_a', 'col2_a', 'col3_a', 'coln_a'),
        ('col1_b', 'col2_b', 'col3_b', 'coln_b')    
) AS t2(col1, col2, col3, coln)
    ON t2.col1 = t1.col1
    AND t2.col2 = t1.col2
    AND t2.col3 = t1.col3

删除与所有值匹配的特定行

1 个答案: