CODEWITHSUNDEEP
mysqlsql
kim kazama
kim kazama

Reputation: 23

SQL: Does having two tables require a join statement?

If I have two conditions in a where statement that is in two different tables, is it required to make a join between them?

like: 

select *
from customer, order 
where customer = 'john'
and order = 'car'

Does it require them to have a join statement because I have two tables in from ?

Upvotes: 1

Views: 52

Answers (2)

Gordon Linoff
Gordon Linoff

Reputation: 1269503

Let me assume that you intend:

select *
from customer c cross join
     orders o
where c.customer = 'john' and o.order = 'car';

This is fine. I might expect that the orders table would have a "customer id" of some sort. But if you want all "john"s cross with all "car"s, then the query does what you intend.

Some people would write this as an inner join:

select *
from customer c join
     orders o
     on c.customer = 'john' and o.order = 'car';

I'm fairy neutral -- except I strongly encourage you to spell out cross join rather than using a comma.

Upvotes: 1

Benjamin Racette
Benjamin Racette

Reputation: 172

Yes you absolutely need to join those two tables to get the results you are looking for.

Upvotes: 0

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