日期:2014-05-17 浏览次数:20443 次
select b,count(1) from (select * from a union all select * from b Union all select * from c . . . union all select * from t) T group by b
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select b,count(*) from ( select * from 表1 union all select * from 表2 Union all select * from 表3 . . . union all select * from 表20 ) tb group by b