Question

Greetings friends,

In my MySQL database, I have ‘MAB’ table which contains information about Gene Ids (GI_ID),and some other gene related information.

‘MAB_CAN’ table can contains the Gene Ids (GI_ID) only relevant to Cancer.

I use following SQL query to get cancer related information from MAB table :

SELECT * FROM MAB WHERE `GI_ID` IN (SELECT `GI ID` FROM `MAB_CAN`)

It takes about 14 Seconds for this query, which is too long.(1605 records).

But the following independent queries it takes short time.

SELECT GI_ID FROM MAB_CAN WHERE 1

• 0.0005 secs (1,605 records)

SELECT * FROM MAB WHERE 1

• 0.0007 sec (31,043 records)

Any tips of optimizing my first query ?

Answer 1

1. replace * with column names
2. create non-clustered index on GI_ID