CODEWITHSUNDEEP
mysqlexists
stack
stack

Reputation: 10228

How to check value exists in table or not?

I have a query like this:

INSERT INTO votes (post_id, user_id, value, date_time)
    SELECT ?,?,?,?,?,?
    FROM $table_name t
    WHERE {if t.id exists $id} limit 1

How can I write this {if t.title exists 'anythin'} in MySQL ?

EDIT: Actually I want to check post is exists in the Posts table before inserting a vote for that post.

Upvotes: 1

Views: 1902

Answers (2)

genespos
genespos

Reputation: 3311

Have you tryed

WHERE EXISTS (SELECT * FROM $Posts_table_name WHERE Id = 'YourPostId');

Edit: You wrote: " Actually I want to check post is exists in the Posts table before inserting a vote for that post."

Best way to do this is to set post_id as foreign key so, if the id doesn't exist the insert query will not have effects

Upvotes: 1

Redbeard011010
Redbeard011010

Reputation: 964

If your goal is to select 'where' data exists, try WHERE t.title IS NOT NULL.

If it is to complete a conditional statement which inserts 'anything' if there is any data, then try (if t.title is not null, 'anything', null)

Upvotes: 2

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