SELECT 1 AS co1, 'a' AS co2 INTO #a UNION SELECT 2, 'a' UNION SELECT 11,'a' UNION SELECT 12, 'a' UNION SELECT 13, 'a' UNION SELECT 14, 'a' UNION SELECT 15, 'a' UNION SELECT 3, 'b' UNION SELECT 7, 'b' UNION SELECT 8, 'b' UNION SELECT 9, 'b' UNION SELE…
以下sql是a,b两张表通过关联条件id修改a表值,如果b表有重复数据记录,选第一条更新,红色条件为附加限制条件,具体视情况而定: UPDATE a SETname = b.fname,pwd = b.lnameFROM bWHERE a.id = b.id AND a.id in (2,3) 以下sql为查询单表中重复记录: select * from b t1 where t1.fname in (select t2.fname from b t2 group by t2.fname ha…
用SQL语句,删除掉重复项只保留一条 在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢1.查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) 2.删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有r…
-------------------------(情景描述) 在我们处理数据时,可能会碰到这种情景: Id Name 1 a,b 2 a 1 a,b,c 对于上面的表数据要求合并同类项Name,得到结果: 1 a,b,c 2 a -------------------------(解决方案) 我们…
用SQL语句,删除掉重复项只保留一条 在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢1.查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) 2.删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有r…