sql查询某字段的相同值
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责编:小采
时间:2020-11-09 08:54:42
sql查询某字段的相同值
sql查询某字段的相同值:sql查询某字段的相同值: SELECT * FROM table WHERE col in (SELECT col FROM table GROUPBY col HAVING COUNT (col)>1); 顺带说一下where和having: select * from tablewhere ···(只能对分组前的属性进行
导读sql查询某字段的相同值:sql查询某字段的相同值: SELECT * FROM table WHERE col in (SELECT col FROM table GROUPBY col HAVING COUNT (col)>1); 顺带说一下where和having: select * from tablewhere ···(只能对分组前的属性进行

sql查询某字段的相同值:
SELECT * FROM table WHERE col in (SELECT col FROM table GROUP?BY col HAVING COUNT (col)?>1);
?
顺带说一下where和having:
select * from table
where ···(只能对分组前的属性进行筛选)
group by ···(按某个字段分组)
having ···(只能对分组后的每个组的整体属性进行筛选,用聚合函数体现)
--不使用group by就默认表的整体为一组
sql查询某字段的相同值
sql查询某字段的相同值:sql查询某字段的相同值: SELECT * FROM table WHERE col in (SELECT col FROM table GROUPBY col HAVING COUNT (col)>1); 顺带说一下where和having: select * from tablewhere ···(只能对分组前的属性进行