(database)(Commonly "join", but see also "outer join") Arelational database operation which selects rows from twotables such that the value in one column of the firsttable also appears in a certain column of the second table.
An example in SQL:
select * from A, Bwhere A.x = B.y
The column names (x and y in this example) are often, but notnecessarily, the same.