Optimise multiple OR query

问题

I have a Database table where I need to validate if a user has entered in the same or partly the same information.

Here is what I'm thinking

The db layout

rec_id (pk), user_id,
name, phone, address_1, address_2, zip, 
company, co_phone, co_address_1, co_address_2, co_zip, 
billing, bi_phone, bi_address_1, bi_address_2, bi_zip

The Query

SELECT rec_id 
FROM tbl_name
WHERE user_id = '123456789'
OR '1112223333' IN (phone, co_phone, bi_phone)
OR 'John Doe' IN (name, business, billing)
OR '12345' IN (zip, co_zip, bi_zip)
OR '123 main street' IN (address_1, co_address_1, bi_address_1)
OR 'po box 123' IN (address_2, co_address_2, bi_address_2)

If any of the data matches (and yes the will be false positives) I need the old rec_id.

Wanted to know if there is a better way to do this?

Thanks

回答1:

For this query to perform well you will need separate indexes for each of the columns you are testing. A combined index on all columns won't help at all for OR conditions (it would help if you had ANDs though).

However I would imagine that your query result in a full table scan regardless of which indexes you add. You might want to try using UNIONs instead of OR to see if that makes a difference:

SELECT rec_id FROM tbl_name WHERE tax_id = '123456789'
UNION
SELECT rec_id FROM tbl_name WHERE phone = '1112223333'
UNION
SELECT rec_id FROM tbl_name WHERE co_phone = '1112223333'
UNION
SELECT rec_id FROM tbl_name WHERE bi_phone = '1112223333'
UNION
SELECT rec_id FROM tbl_name WHERE name = 'John Doe'
UNION
SELECT rec_id FROM tbl_name WHERE business = 'John Doe'
UNION
SELECT rec_id FROM tbl_name WHERE billing = 'John Doe'
UNION
-- etc...

The idea of rewriting it like this is that now each subquery will be able to use an index (assuming of course that you have added the necessary indexes).

来源：https://stackoverflow.com/questions/4741089/optimise-multiple-or-query

标签

postgresql

sqlperformance

sql-optimization