SQL分組統(tǒng)計(jì)并排序？with tmp as(select row_number() over(order by count(val)) as rn，val，count(val) as cnum fr

SQL分組統(tǒng)計(jì)并排序？

with tmp as

(select row_number() over(order by count(val)) as rn，val，count(val) as cnum from table1 group by val)

select * from tmp where rn

要想?yún)^(qū)別并列現(xiàn)象還要復(fù)雜一些，可能簡(jiǎn)單的語(yǔ)句解決不了

sql同一個(gè)字段先分組再排序？

應(yīng)該是先篩選比較好，會(huì)減少分組的運(yùn)算量。 sql 默認(rèn)的優(yōu)先級(jí)是 from>where>group by>select>order by where在group by 前執(zhí)行，會(huì)減少group by 的運(yùn)算量。

oracleSQL用select過(guò)程進(jìn)行分組排序查詢？

實(shí)現(xiàn)思路：通過(guò)select進(jìn)行查詢，通過(guò)group by進(jìn)行分組后，之后通過(guò)order by進(jìn)行排序。sql：select username from tablename order by username desc group by username以上就是通過(guò)username字段降序排序（升序是ASC、降序是DESC）。