在where子句中使用join

Question

SELECT * FROM Base b 
JOIN Departement d ON b.d_id = d.d_id 
JOIN Block bl ON b.b_id = bl.b_id 
JOIN Model m ON b.m_id = m.m_id 
WHERE (b.s_no LIKE '%' + @search +'%' 
OR b.ser_no LIKE '%' + @search + '%'
OR b.user_name LIKE '%' + @search + '%' 
OR d.d_id LIKE '%' + @search + '%' 
OR bl.b_id LIKE '%' + @search + '%' 
OR m.m_id LIKE '%' + @search + '%' 
OR d.d_name LIKE '%' + @search + '%' 
OR m.m_name LIKE '%' + @search + '%') ";

I try to write a sql command to search the database. But it doesn't work. Is this a false usage?

Answer 1

Maybe you need outer joins instead of inner ones.. Not sure what is wrong in your case, but try using left joins. Probably you just have data in one table, but don't have corresponding data in another one..

instead of

 SELECT * FROM Base b 
 JOIN Departement d ON b.d_id = d.d_id 
 JOIN Block bl ON b.b_id = bl.b_id 
 JOIN Model m ON b.m_id = m.m_id 
 WHERE (b.s_no LIKE '%' + @search +'%' 
 OR b.ser_no LIKE '%' + @search + '%'
 OR b.user_name LIKE '%' + @search + '%' 
 OR d.d_id LIKE '%' + @search + '%' 
 OR bl.b_id LIKE '%' + @search + '%' 
 OR m.m_id LIKE '%' + @search + '%' 
 OR d.d_name LIKE '%' + @search + '%' 
 OR m.m_name LIKE '%' + @search + '%') ";

try this:

 SELECT * FROM Base b 
 LEFT JOIN Departement d ON b.d_id = d.d_id 
 LEFT JOIN Block bl ON b.b_id = bl.b_id 
 LEFT JOIN Model m ON b.m_id = m.m_id 
 WHERE (b.s_no LIKE '%' + @search +'%' 
 OR b.ser_no LIKE '%' + @search + '%'
 OR b.user_name LIKE '%' + @search + '%' 
 OR d.d_id LIKE '%' + @search + '%' 
 OR bl.b_id LIKE '%' + @search + '%' 
 OR m.m_id LIKE '%' + @search + '%' 
 OR d.d_name LIKE '%' + @search + '%' 
 OR m.m_name LIKE '%' + @search + '%') ";

And if you tell us what is wrong in details - we will be able to give more detailed assumptions :)