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[英]How can I select records from two different tables in one MySQL query?
[英]MySql - Select user name from two different tables in one query
我有3張桌子
我想選擇最喜歡的用戶的名稱和得分最高的用戶的名稱。 但是我的問題是,當我編寫查詢時,我在那里重復了name
字段。 我該怎么辦?
使用別名可能會幫助您
SELECT a.id as id_a,
b.id as id_b,
c.id as id_c
from a
inner join b
on a.id = b.a_id
inner join c
on a.id = c.a_id
您可能正在使用SELECT *
。 您應該指定字段名稱:
SELECT u.user_id, u.name, li.numOfLikes FROM users u INNER JOIN likes li ON (u.user_id=li.user_id) ORDER BY li.numOfLikes
SELECT u.user_id, u.name, s.score FROM users INNER JOIN scores s ON (u.user_id=s.user_id) ORDER BY s.score
我在查詢中使用以下三個表
要獲取具有最高分數的用戶的詳細信息,請使用以下
select usrtbl.username,usrtbl.userid,tbl2.score from usertable usrtbl inner join table2 tbl2 on usrtbl.userid=tbl2.userid order by tbl2.score
desc limit 1
要獲得最多點贊次數的用戶的詳細信息,請使用以下代碼
select usrtbl.username,usrtbl.userid,tbl3.numOfLikes from usertable usrtbl inner join table3 tbl3 on usrtbl.userid=tbl3.userid order by tbl3.numOfLikes
desc limit 1
要獲得全部查詢,請使用以下查詢
select usrtbl.username as 'user_with_max_score',usrtbl.userid as 'userid_of_user_with_max_score',
tbl2.score as 'max_score',usrtbl2.username as 'user_with_max_likes',usrtbl2.userid as 'userid_of_user_with_max_score' ,
tbl3.numOfLikes as 'max_likes' from usertable usrtbl2 inner join table3 tbl3 inner join usertable usrtbl inner join table2 tbl2
on usrtbl.userid=tbl2.userid and usrtbl2.userid=tbl3.userid order by tbl2.score desc,tbl3.numOfLikes desc
limit 1
您可以選擇表名 .name
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