16 May

Joins: inner, outer, left, right

In (My)SQL, join is a means for combining records from two tables into a single set which can be either returned as is or used in another join. In order to perform the operation a join has to define the relationship between records in either table, as well as the way it will evaluate the relationship. The relationship itself is created through a set of conditions that are part of the join and usually are put inside ON clause. The rest is determined through a join type, which can either be an inner join or an outer join.

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