如何从我知道第二张桌子的ID的第一张桌子

Question

I need to get both table and here is the table structure

Table A

• UserID
• Username
• Status
• IntroCode

Table B

• IntroCode
• UserID

I want to get the table a data and join with table b on tblA.IntroCode = tblB.IntroCode, then get the username of tblB.userID. How can i do such join ?

I tried half way and stuck in the middle, please help. Thanks for reply

Answer 1

This is just a simple join.

SELECT  a.*, b.*    -- select your desired columns here
FROM    tableA a
        INNER JOIN tableB b
            ON a.IntroCode = b.IntroCode
WHERE   b.userid = valueHere

UPDATE 1

SELECT  a.UserID, 
        a.`Username` OrigUserName,
        a.`Status`,
        c.`Username` IntroUserName
FROM    tableA a
        INNER JOIN tableB b
            ON a.IntroCode = b.IntroCode
        INNER JOIN tableA c
            ON b.userID = c.userID
-- WHERE b.UserID = valueHere       -- extra condition here

Answer 2

SELECT column_name(s)
FROM TableA
LEFT JOIN TableB
ON TableA.UserID=TableB.UserID

Answer 3

SELECT B.userID from TableA A
LEFT JOIN TableB B on A.IntroCode=B.IntroCode

Answer 4

select a.*,b.IntroCode  from TableA a left join TableB b
on a.IntroCode = b.IntroCode 

Answer 5

you have to give the columns with same name an unique value:

SELECT  a.UserID as uid_a, b.UserID as uid_b
FROM    tableA a
INNER JOIN tableB b ON a.IntroCode = b.IntroCode
WHERE   b.UserID = 1

Answer 6

使用此查询。

 SELECT TableA.Username FROM TableA JOIN TableB ON (TableA.IntroCode = TableB.IntroCode);

Answer 7

使用此查询

SELECT  *  FROM tblA INNER JOIN tblB ON tblA.IntroCode = tblB.IntroCode where tblB.userid = value