how to decrease executing select query time - mysql

Question

decreasing running time (select query executing time)
even query is not working
it is reducing code line
there are 80 tables
select
(ant_return_loss_pass='pass')+(ant_cross_isolation_pass='pass') as pass_count,
(ant_return_loss_pass='fail')+(ant_cross_isolation_pass='fail') as fail_count,
(ant_return_loss_pass='') +(ant_cross_isolation_pass='') as blank_count
from
(
select A.serial_no,
A.pass_fail as ant_return_loss_pass
from ant_return_loss A,
(
select max(register_date) as date
from ant_return_loss
where 1=1
and serial_no >= '184500074'
and serial_no <= '184500076'
group by serial_no
) B
where 1 = 1
and A.register_date = B.date
)AA
,(
select A.serial_no,
A.pass_fail as ant_cross_isolation_pass
from ant_cross_isolation A,
(
select max(register_date) as date
from ant_cross_isolation
where 1=1
and serial_no >= '184500074'
and serial_no <= '184500076'
group by serial_no
) B
where 1 = 1
and A.register_date = B.date
)BB
where 1=1
and AA.serial_no = BB.serial_no
not working or working 600 sec

Answer 1

The query below uses explicit join syntax and case expressions to make you query easier to understand:
SELECT
COUNT( CASE WHEN ant_return_loss_pass = 'pass' AND
ant_cross_isolation_pass = 'pass' THEN 1 END ) AS pass_count
, COUNT( CASE WHEN ant_return_loss_pass = 'fail' AND
ant_cross_isolation_pass = 'fail' THEN 1 END ) AS fail_count
, COUNT( CASE WHEN ant_return_loss_pass = '' AND
ant_cross_isolation_pass = '' THEN 1 END ) AS blank_count
FROM (
SELECT
A.serial_no
, A.pass_fail AS ant_return_loss_pass
FROM ant_return_loss A
INNER JOIN (
SELECT MAX( register_date ) AS date
FROM ant_return_loss
WHERE serial_no >= '184500074'
AND serial_no <= '184500076'
GROUP BY serial_no
) B ON A.register_date = B.date
) AA
INNER JOIN (
SELECT
A.serial_no
, A.pass_fail AS ant_cross_isolation_pass
FROM ant_cross_isolation A
INNER JOIN (
SELECT MAX( register_date ) AS date
FROM ant_cross_isolation
WHERE serial_no >= '184500074'
AND serial_no <= '184500076'
GROUP BY serial_no
) B ON A.register_date = B.date
) BB ON AA.serial_no = BB.serial_no
To examine if this can be improved for performance however requires access to your database. For example do you indexes for ant_return_loss.serial_no or ant_cross_isolation.serial_no these will aid the where clauses of the subqueries.
Have you run any explain plans on the query? see: https://dev.mysql.com/doc/refman/5.7/en/explain.html
Note to avoid long running time you can use explain on separated portions of the overall query, look for indexes that may assist: e.g.
explain
SELECT MAX( register_date ) AS date
FROM ant_return_loss
WHERE serial_no >= '184500074'
AND serial_no <= '184500076'
GROUP BY serial_no
then:
explain
SELECT
A.serial_no
, A.pass_fail AS ant_return_loss_pass
FROM ant_return_loss A
INNER JOIN (
SELECT MAX( register_date ) AS date
FROM ant_return_loss
WHERE serial_no >= '184500074'
AND serial_no <= '184500076'
GROUP BY serial_no
) B ON A.register_date = B.date
until you have examined all portions for way to improve performance.