How can I EXPLAIN several consecutive queries without executing them?

Question

Suppose I have a pair of arbitrary SQL queries, each one depending upon the former ones, e.g.

CREATE VIEW v1 ( c3 ) AS SELECT c1 + c2 FROM t1;
SELECT sum(c3) FROM v1;
DROP VIEW v1;

(but note I am not asking about these specific queries - this is just an example; assume I get the queries from a file and do not know them in advance.)

Now, I want to get my DBMS to EXPLAIN its plan for all of my queries (or an arbitrary query in the middle, it's the same problem essentially) - but I do not want it to actually execute any of them.

Is this possible with (1) MySQL? (2) PostgreSQL? (3) MonetDB?

Answer 1

PostgreSQL

You may use the explain statements as follows.

BEGIN;
EXPLAIN ANALYZE ...;
ROLLBACK;

Refer this, documentation answers your question.

MonetDB

Similarly to the above, except that the transaction-related statements are BEGIN TRANSACTION and ROLLBACK statements (assuming that you are in auto-commit mode to begin with).

Refer this.

MySQL

MySQL explain it self does what you need. No need to ROLLBACK.

Refer this answer.