Oracle Semi JoinSemi-join is introduced in Oracle 8.0. It provides an efficient method of performing a WHERE EXISTS sub-query. A semi-join returns one copy of each row in first table for which at least one match is found. Semi-joins are written using the EXISTS construct. Oracle Semi Join ExampleLet's take two tables "departments" and "customer" Departments table Customer table Execute this query Output Difference between anti-join and semi-joinWhile a semi-join returns one copy of each row in the first table for which at least one match is found, an anti-join returns one copy of each row in the first table for which no match is found. Next TopicOracle Procedure |