Optimization of inner joins in mysql query

Databases
,
1

I have been working with mysql almost 3 years and now i am struck very badly and it is all about the query performance because the tables i am dealing with having records in millions so please suggest me what to do.

I have to fetch dada from 6 tables

table_1
table_2
table_3
table_4
table_5
table_6

Now i tell you how -

table_1/table_2/table_3/table_4 have left join and fetching id out of it. - Lets say this is step A .
Then I fetch all order_id from table_6 - Let’s say this is step B.

Now i search step A using IN(id) AND step B using NOT IN(order_id) into table_5 which screw my query because table_5 has 300k records and table_6 has 200k records so please can someone suggest me what to do?

If my question is not clear then i can send screenshot also.

Looking forward to hear from you soon and thanks in advance!

2

You should post your DB schema (not pictures). This smells of a really bad database design.

3

First of all thanks for the response benanamen and yes i send you schema.
And to be honest i can not change the schema.

4

Well, lets see what your working with so we can figure something out.

5

please run SHOW CREATE TABLE tablename for each table – this will also show us which indexes the tables have

also please post your actual query

6

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