Question

I have a QUERY which is like

SELECT COUNT(*) as cnt 
    FROM tbl_docatrtypegroupdoctype, 
         tbl_doctype, 
         tbl_docatrtypegroup 
    WHERE 1=1  
          AND 
         (tbl_doctype.doctype_name like '%Payment%' 
            OR tbl_doctype.doctype_name like'% Payment' 
            OR tbl_doctype.doctype_name like ' Payment%' ) 
    LIMIT 1

Now in the above query I need to count the number of records in table “tbl_docatrtypegroupdoctype” under the conditons given in where clause, whenever i execute the query, I get 77 count, but actual count in DB is 12.

What could be the problem with this query and how can I rectify it?

Ant help will be appriciated

Thanks

Answer 1

You need to specify your join conditions. What happens if you don’t is a cross product which is not what you want.

 SELECT COUNT(*) as cnt 
FROM tbl_docatrtypegroupdoctype JOIN  
     tbl_doctype on (THE CONDITION) JOIN 
     tbl_docatrtypegroup on (THE CONDITION)

Alternatively the JOIN conditions can be spefified in the WHERE clause.

---

In the where clause:

  WHERE table1.field1 = table2.field2 AND table2.field3 = table3.field4

The fields that you join on must be semantically related in some way of course.