使用多列分组删除

Question

我想删除此查询返回的所有行。

SELECT col1, col2, col3 FROM myTable GROUP BY col1, col2, col3 HAVING count(*) > 1;

我试过了，但它给我一个语法错误。

DELETE FROM myTable WHERE col1, col2, col3 IN ( 
                       SELECT col1, col2, col3 FROM   ( 
                              SELECT   col1, col2, col3 FROM myTable 
                              GROUP BY col1, col2, col3 HAVING count(*) > 1 ) 
                            t );

Answer 1

对您的 table

使用 INNER JOIN

DELETE t1 FROM myTable t1
        INNER JOIN ( 
                       SELECT col1, col2, col3 FROM   ( 
                              SELECT   col1, col2, col3 FROM myTable 
                              GROUP BY col1, col2, col3 HAVING count(*) > 1 ) 
                            t )
    t2 ON t2.rcol1 = t1.rcol1 AND t2.col2 = t1.col AND t2.col3 = t1.col3;

但是你应该在测试数据库上测试它，因为我不认为你的select识别正确的行，最好有一个UNIQUE 列，将标识正确的行，因为这将删除所有行

使用多列分组删除

Delete using group by with multiple columns

mysql

group-by

sql-delete