Why would you not use a join when doing a SQL query between two tables?

Why would one use the following query: select a.item, b.item from a,b where http://a.id = http://b.id Instead of: select a.item, b.item from a join b on http://a.id = http://b.id
Answer:

The two queries as presented are identical. The latter syntax has the ability to be extended to other kinds of joins. CROSS JOIN NATURAL JOIN LEFT JOIN RIGHT JOIN FULL OUTER JOIN The former syntax does not allow for that flexibility and using the former syntax type, you have to resort to database specific representations (like +=).

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Other answers

The first is in "traditional" syntax, second in Ansi'92. It's matter of personal preferences. My favorite is Ansi because I've got used to it first. Many people prefer traditions. Btw. they aren't equal - the first's inner join [intersect of a and b], second left join [all from a, matches from b].

Jozo Kovac

I don't know any reason, other as perhaps database specific ones to ban the JOIN. In the "old days" you couldn't use a JOIN in Oracle, but other SQL languages does support it from the beginning. It's all in the database query interpreter or a JOIN is handled differently as a "key = key". So my advise is to check it for your database engine by checking the response time of both methods to see the difference. Nic;o)

Nico Altink

refer answer here :

Deepak Pandey

I always find first one easy and logically more understandable.

Mohammad Imran Khan

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