Check the Execution Time Period of SQL Queries

_MANUAL.md

Start the profiler with

SET profiling = 1;

Then execute your Query.

With

SHOW PROFILES;

you see a list of queries the profiler has statistics for. And finally you choose which query to examine with

SHOW PROFILE FOR QUERY 1;

or whatever number your query has.

What you get is a list where exactly how much time was spent during the query.

More info in the manual.

_query_time.sql

-- First, I started the profiler with :
SET
    profiling = 1;
    
-- Then, I executed the query with sub-query.
SELECT
    * 
FROM
    class 
WHERE
    name IN 
    (
        SELECT
            name 
        FROM
            class 
        WHERE
            fid = "f501"
    )
;

-- Again, I executed the normal query.
SELECT
    * 
FROM
    class 
WHERE
    fid = "f501";
    
-- Finally, I got the stats.
show profiles;

OUTPUT.md

The output of the above query was :

Hence, it can be concluded that sub query takes more time to execute than the normal SQL query.