-------------------------(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…

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…

用SQL语句,删除掉重复项只保留一条 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…

合并字段用+号连接就可以了,不过要判断是不是有的合并项为NULL.如果其中一项为NULL,则整个合并字段为NULL. (IsNull(a.supplier, '')  + IsNull(a.po, '')  +  IsNull(a.inv, '') + IsNull(a.REMARK, '') ) as REMARK 用IsNull函数来规避这种情况…

--联查select n.*,t.Name from News n join Type_News tn on n.Id=tn.NId join Types t on t.Id=tn.TId --拼接并插入临时表select aaa.Title,aaa.Content, stuff((select ',' + ttt.Name from (select n.*,t.Name from News n join Type_News tn on n.Id=tn.NId join Types t on t…

1.开始数据结构如下: 2.转为如下图: 使用如下SQL语句: ---横向转丛向 select name '姓名', max(case when course='语文' then score end) as '语文', max(case when course='数学' then score end) as '数学', max(case when course='物理' then score end) as '物理' from t_score group by name 3.以及转为如下图: (…

需求  查询小时气象表中 同一日期.同一城市.同意检测站点  首要污染物出现出书最多的记录 第一步: 添加 排序字段 select StationID,RecordDate,CityID,Primary_Pollutant,ROW_NUMBER() over(partition by StationID,RecordDate,CityID order by count(0) desc ) as Numfrom  T_AirHourly group by StationID,RecordDate,…

STUFF ( character_expression , start , length ,character_expression ) select TcodMedInst_GUID,stuff((SELECT ',' + DeptName+'|'+guid FROM TcodDeptHosContrast AS t WHERE t.TcodMedInst_GUID = tb.TcodMedInst_GUID FOR xml path('')), 1, 1, '') Dept from Tc…

select count(1),content_id,keyword_id from tb_content_keyword_relation group by content_id,keyword_id having count(1)>1 order by count(1) desc SELECT id FROM tb_bds_sys_user WHERE del_flag = '0' AND id IN ( SELECT user_id FROM tb_bds_sys_user_role WH…