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EJB QL 'LIKE' CLAUSE

Posted on 2003-12-04
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Last Modified: 2013-11-24
Hi. I am currently making a search module using EJB QL for the search Query (Oracle Database). I am having a problem on searching with NULL values. It goes this way:

This is the current EJB QL that we use:

select * from TABLE1 t1,TABLE2 t2 WHERE t1.deal_project_id=t2.project_id
AND t2.title LIKE ?1
AND t2.description LIKE ?2
AND t1.contract LIKE ?3
AND t1.deal_type_id LIKE ?4
and t1.network_id=?5

If the user did not specify any string in the textfield we just supply the %% escape character. For example:

select * from TABLE1 t1,TABLE2 t2 WHERE t1.deal_project_id=t2.project_id
AND t2.title LIKE '%%'
AND t2.description LIKE '%%'
AND t1.contract LIKE '%%'
AND t1.deal_type_id LIKE '%%'
and t1.network_id=1

But the problem is, instead of including the columns with NULL in them (Since '%%" means that the user did not specify a criteria in the front end), it ignores it. I know that the solutiom to this is to check if one or more of the criteria is NULL but this will require a lot of EJB finder methods. Does anyone have a good solution to this problem? Your help will be greatly appreciated. Thanks a lot.

Regards!
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Question by:animor
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6 Comments
 
LVL 30

Expert Comment

by:Mayank S
ID: 9880091
I prefer using LIKE '%%' for all cases.... even in the first case, I would have used LIKE '%1'. Did you try printing the query and see what it is. Run the same query in Oracle and see the result.
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LVL 40

Accepted Solution

by:
Richard Quadling earned 20 total points
ID: 9881861
Can you try ...

SELECT
      *
FROM
      TABLE1 t1,
      TABLE2 t2
WHERE
      t1.deal_project_id = t2.project_id
      AND (t2.title LIKE '%%' OR t2.title IS NULL)
      AND (t2.description LIKE '%%' OR t2.description IS NULL)
      AND (t1.contract LIKE '%%' OR t1.contract IS NULL)
      AND (t1.deal_type_id LIKE '%%' OR t1.deal_type_id IS NULL)
      AND (t1.network_id=1 or t1.network_id IS NULL);


Regards,

Richard.
0
 
LVL 40

Expert Comment

by:Richard Quadling
ID: 9881880
A better way would be to build a query in code.

e.g.

Start with

SELECT * FROM TABLE1 t1, TABLE2, t2 WHERE t1.deal_project_id = t2.project_id

Then, for each of the search criteria the end user can input something into, check to see if it is not blank and then append the string ...

"AND field LIKE value_user_typed"

or

"AND field = value_user_typed"

depending upon what you want.

This way if no criteria entered, no filtering is done.

Richard.
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Author Comment

by:animor
ID: 9883119
Thanks for the reply guys. RQuadling's first suggestion is good enough to make it work. Since I will be using EJB and we would like to minimize the number of finder methods, it really helps if we can use only one SQL statement to execute the search.

(awards him the points)

Thank you very much =)
0
 
LVL 40

Expert Comment

by:Richard Quadling
ID: 9883148
Thank you.

And I only stumbled into this area today as an accident, looking for the PHP questions!
0
 

Author Comment

by:animor
ID: 9883395
you're welcome. i just noticed that it wont work if the user provides a criteria and still stumbles upon null values, the query will return even those that have null values. Maybe i should check first the categories supplied as what you suggested in your second post.
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