Joining 4 Tables in SQL Server Using Join

问题

Hi Friends I have to join 4 tables in SQL Server and need to Show Specific Coulmns in Data Grid View

First Table : emp_details

Second Table : tbl_designation

Third Table : tbl_empcontribution

Forth table : tbl_empdeduction

Columns need to show in Data Grid View is

1.From First Table i need to show emp_id, emp_name , emp_pf
2.from Second Table i need to show designation_name
3.from third Table i need to show pfacc1 and pfacc2
4.From Fourth Table i need to show pf_percent and pf_max

Try to Reply to this as soon as possible Friends...Thanks..

回答1:

Below is the query you need, you should consider keeping your naming conventions consistent because this helps visually and reduce bugs when writing code.

SELECT ed.emp_id, ed.emp_name , ed.emp_pf, emd.designation_name, te.pfacc1, te.pfacc2, temp. pf_percent, temp.pf_max
FROM dbo.emp_details AS ed
LEFT JOIN dbo.emp_designation AS emd ON emd.designation_id = ed.emp_designation 
LEFT JOIN dbo.tbl_empcontribution AS te ON te.eid = ed.emp_id
LEFT JOIN dbo.tbl_empdeduction AS temp ON temp.eid = ed.emp_id

回答2:

    SELECT e1.emp_id, e1.emp_name, e1.emp_pf, e2. designation_name, e3.pfacc1, e3.pfacc2, e4. pf_percent,  e4.pf_max 

from emp_details e1, tbl_designation e2, tbl_empcontribution e3, tbl_empdeduction e4

 where e1.emp_id= e2.emp_id and e2.emp_id=e3.emp_id and e3.emp_id= e4.emp_id;

assuming you have emp_id as foreign key in all 4 tables

来源：https://stackoverflow.com/questions/17440556/joining-4-tables-in-sql-server-using-join