Can we use join without on condition?

Can you use join without on?

Omit the ON clause from the JOIN statement In MySQL, it's possible to have a JOIN statement without ON as ON is an optional clause. You can just simplly JOIN two tables like this: SELECT * FROM table_a JOIN table_b; It will match each row from table_a to every row in table_b .

Can we use LEFT join without on condition?

For LEFT JOIN you must have ON but you can use ON TRUE . Which causes the join to be the equivalent of a cross join...... there simply is no point to using left join without a qualification to that join where some rows are matched and some might not be matched. ON TRUE does not permit some rows to be unmatched.

Can we put or condition in join?

putting conditions in join improve performance for large amount of data with properly indexed tables. @Shahdat if you are getting that significant a performance difference moving your filter conditions from the where clause to the inner join you need to post those execution plans.

Can we use join without foreign key?

In this blog, we will understand how to join two or more SQL tables without using a foreign key. We will also get an overview of Join and Keys in SQL. In this blog, we will understand what a SQL Join is and how to join two or more SQL tables without using a foreign key.