SQL query for empty string

[GeekGrok]

I am trying to execute the following SQl query, SELECT * FROM Failure WHERE ID = '123' AND RepairAction = ' ';, using the DB Tools Execute Query.vi. This query never finds the record in my database. My database contains a record where the ID filed contains the value of '123' and the RepairAction field is an empty string. If I remove the 'AND RepairAction ' ';' text from my query statement, the record is found. I believe my problem is that I am not using the correct syntax to describe and empty string. I have tried the following: '', ' ', "", " ", and NULL as empty string arguments, and none of these work.

I was hoping someone might be able to tell me what the correct syntax is for an empty string or if there is another approach I need to take.

Thank you in advance for your help,

Jim

[NitzZ]

Hi,

While creating your table "Failure", was the column "ID" delclared as intiger or varchar? If it is intiger and you use '123' , it wont return the results. You will have to try without the inverted comas ' '.

Regards,

Nitzz

(Giver Kudos to good Answers, Mark it as a solution if your problem is Solved;))

[Cerati]

Hi there Jim,

you could try modifying your command just a little bit. Try this:

...AND RepairAction is null;

It works for me in Oracle.

Cheers,

Cerati

[GeekGrok]

The column ID is varchar. As previously stated the query works when I leave out the RepairAction search. So I think the problem is with my syntax for declaring an empty string in the SQL query.

Thank you,

Jim

[GeekGrok]

Hi Cerati,

 I tried your suggestion, null, and still did not return a record.

Thank you. I appreciate your assistance.

Jim

[Cerati · Accepted solution]

Jim,

Just to be sure, did you use "is" instead of " = " in that command ?

That makes the whole difference in that command.

Cerati

[sebster]

Useful SQL resource (including IS NULL)

http://www.w3schools.com/sql/sql_null_values.asp

[GeekGrok]

Cerati,

"is" is the solution. Thank you for pointing out this 'minor' detail. I had initially tested you suggestion using the "=". When I replaced this with "is" per your follow up, the record was read.

Thank you again,

Jim

[Cerati]

Okey, I'm glad it worked for you as well

Cheers,

Cerati