<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
How many types of sql joins does mysql supports?<|im_end|>
<|im_start|>assistant
MySQL supports four types of SQL joins: inner join, left join, right join, and full outer join. Here's a brief explanation of each type:

1. Inner join: Returns only the matching rows between the two tables based on the specified condition.
2. Left join: Returns all the rows from the left table and matching rows from the right table based on the specified condition. If there is no match in the right table, the result will contain NULL values.
3. Right join: Returns all the rows from the right table and matching rows from the left table based on the specified condition. If there is no match in the left table, the result will contain NULL values.
4. Full outer join: Returns all the rows from both tables, matching rows where available, and NULL values where there is no match.

Note that MySQL also supports a cross join, which is not technically a join type, but rather a cartesian product of the two tables. A cross join returns all possible combinations of rows between the two tables.<|im_end|>
<|im_start|>user
How many types of SQL JOINS does PostgreSQL support? Compare and contrast with the above list.<|im_end|>
<|im_start|>assistant
PostgreSQL supports 4 different types of JOINS:

1. Inner Join: Returns matching data from both tables; functions in the same way as an Inner Join in MySQL
2. Full Outer Join: Returns matching data and unmatched data from both tables; functions the same as Cross Join in MySQL
3. Left Outer Join/Left Join: Returns matching data from both tables and all unmatched data from the left table; Same as Left Join in MySQL
4. Right Outer Join/Right Join: Returns matching data from both tables and all unmatched data from the right table; Same as Right Join in MySQL

I hope that this information helps, as both MySQL and PostgreSQL support the same 4 types of JOIN clauses, albeit by slightly different names.<|im_end|>
<|im_start|>user
what join types do postgresql support?<|im_end|>
<|im_start|>assistant
PostgreSQL has the following types of JOIN clauses:
1. `INNER JOIN`: Returns rows with matching values in both tables.
2. `CROSS JOIN`: Returns a Cartesian Product of rows in both tables. In other words, all combinations of rows between the two tables. Warning: this can generate a lot of rows! Unlike other join types, there is no `ON` clause.
4. `FULL OUTER JOIN`: Returns all rows from both tables. For rows in either table which do not match, the columns otherwise to be supplied by the other table are `NULL` values instead. This is equivalent to all the rows from a `LEFT OUTER JOIN` plus all the rows from a `RIGHT OUTER JOIN`.
5. `LEFT OUTER JOIN` (aka `LEFT JOIN`): Returns all rows from the left table. Where these match rows from the right table, information from the right table is included. Otherwise, these values are `NULL`.
6. `RIGHT OUTER JOIN` (aka `RIGHT JOIN`): Returns rows from the right table. Where these match rows from the left table, information from the left table is included. Otherwise, these values are `NULL`.
7. `NATURAL JOIN`: Returns a join where rows have the same values for columns with the same names. This includes `NATURAL INNER JOIN`, `NATURAL LEFT JOIN`, and `NATURAL RIGHT JOIN`.<|im_end|>