PostgreSQL syntax check without running the query

Question

I want to verify the syntax of files containing sql queries before they can be committed in my CVS project.

In order to do that, I have a commitinfo script, but I h

Answer 1

One way would be to put it into a transaction that you roll back at the end:

BEGIN;
<query>;
<query>;
<query>;
ROLLBACK;

Be aware that there are some effects that cannot be rolled back, like dblink calls, or anything written to the file system or incremented sequences.

I would advise cloning your database for testing purposes.

Answer 2

You could just wrap it in SELECT 1 ( <your query> ) AS a WHERE 1 = 0;

It'll fail on validation but it won't actually execute. Here's an example query plan:

Result  (cost=0.00..0.01 rows=1 width=0)
  One-Time Filter: false

Answer 3

Use this trick to validate PostgreSQL code syntax:

DO $SYNTAX_CHECK$ BEGIN RETURN;
    -- insert your SQL code here
END; $SYNTAX_CHECK$;

Answer 4

You can run queries iside postgresql function and raise exception in the end. All changes will be rolled back. For example:

CREATE OR REPLACE FUNCTION run_test(_sp character varying)
  RETURNS character varying AS
$BODY$
BEGIN
  EXECUTE 'SELECT ' || _sp;
  RAISE EXCEPTION '#OK';
EXCEPTION
  WHEN others THEN
    RETURN SQLERRM;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

Another sollution - plpgsql_check extension (on github), the next incarnation of pgpsql_lint

Answer 5

EXPLAIN (without ANALYZE) will parse the query and prepare an execution plan, without actually executing it.

https://www.postgresql.org/docs/current/static/sql-explain.html

Answer 6

I'm usually use Mimer online SQL validator, the only thing is that it check SQL syntax for standard SQL :

• SQL-92
• SQL-99
• SQL-03

and not specific for the PostgreSQL ... However if you write code following the standard you can use it and it work well ...