SQL JOIN queries execution results as sets processing

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Inner JOIN

This is the simplest, most understood Join and is the most common. This query will return all of the records in the left table (table A) that have a matching record in the right table (table B).

Left JOIN

This query will return all of the records in the left table (table A) regardless if any of those records have a match in the right table (table B). It will also return any matching records from the right table.

Right JOIN

This query will return all of the records in the right table (table B) regardless if any of those records have a match in the left table (table A). It will also return any matching records from the left table.

Outer JOIN

This Join can also be referred to as a FULL OUTER JOIN or a FULL JOIN. This query will return all of the records from both tables, joining records from the left table (table A) that match records from the right table (table B).

Left Excluding JOIN

This query will return all of the records in the left table (table A) that do not match any records in the right table (table B).

Right Excluding JOIN

This query will return all of the records in the right table (table B) that do not match any records in the left table (table A).

Outer Excluding JOIN

This query will return all of the records in the left table (table A) and all of the records in the right table (table B) that do not match. I have yet to have a need for using this type of Join, but all of the others, I use quite frequently.

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