在奇怪的要求中加入mysql中的三个表

Question

I have three tables in my db.

Table A has the fields

KEYID | KeyName
27    | Income
28    | Account Number

Table B has the fields

UserID | Email          | Name | Phone
481    | [e-mail] | test | 99999999

Table C has the fields

ID | KEYID | UserID | Value
1  |   27  |   481  | 10,000

I need to display the table fields headers are:

UserID | Email          | Name |   Phone  | Income

and the table values should be like this:

 481   | [e-mail] | test | 99999999 | 10,000

I can get the KeyIDs which should be displayed in the table. In this example the KeyIDs string is '27' . I tried with joining and i can fetch & display the value in the table. but i dont know how i can show the key name as table header.

Any Idea.?

Answer 1

You can use a pair of inner join

select b.UserID, b.Email , b.Name, c.value as income 
from   tableB as b inner join tableC as C on b.userID = c.userId
inner join tableA as a on a.keyID = c.keyID 
and a.keyname = 'Income';     

and the query you provided in comment

select 
      b.UserID
    , b.Email 
    , b.Name
    , Group_Concat(Distinct Concat(c.keyID,’^:^’,c.value) 
                          Order By c.id Separator ‘;’) As Keyvalues 
    from tableB as b 
    inner join tableC as C on b.userID = c.userId 
    inner join tableA as a on a.keyID = c.keyID;  

and with CASE should be

 select 
      b.UserID
    , b.Email 
    , b.Name
    , Group_Concat(Distinct CASE 
            WHEN c.keyID IN ('1,23,10') THEN Concat(c.keyID,’^:^’,c.value) END  
            Order By c.id Separator ‘;’) As Keyvalues 
    from tableB as b 
    inner join tableC as C on b.userID = c.userId 
    inner join tableA as a on a.keyID = c.keyID;