标签:sql
sql如何去重查询
sql去重查询的方法:重复记录根据单个字段peopleId来判断,使用语句删除,代码为【where peopleId in (select peopleId from people group by peopleId...
SQL中select语句的语法结构是什么?
SQL中select语句的语法结构是:“SELECT select_list [ INTO..] FROM table_name [ WHERE...] [ GROUP BY...][ HAVING...][ ORDER BY...];”。