CODEWITHSUNDEEP
postgresql
Ashwin
Ashwin

Reputation: 13517

Check if a row exists or not in postgresql

I have seen many posts about this in SO. But I could not get an answer. I want to the query to check if a particular row exists or not in a table. If it exists, it should return me a string true and stop the search there itself and if not return false.

Upvotes: 21

Views: 48880

Answers (2)

Tometzky
Tometzky

Reputation: 23890

select
  case when exists (select true from table_name where table_column=?)
    then 'true'
    else 'false'
  end;

But it would be better to just return boolean instead of string:

select exists (select true from table_name where table_column=?);

Upvotes: 61

wildplasser
wildplasser

Reputation: 44230

Spoiler:

-- EXPLAIN ANALYZE
WITH magic AS (
        WITH lousy AS ( SELECT * FROM one  WHERE num = -1)
        SELECT 'True'::text AS truth
        WHERE EXISTS  (SELECT * FROM lousy)
        UNION ALL
        SELECT 'False'::text AS truth
        WHERE NOT EXISTS (SELECT * FROM lousy)
        )
SELECT *
FROM magic
        ;

Upvotes: -17

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