Latest Interview Questions on SQL

SQL queries which contain set operations are called compound queries. Union, Union All, Intersect or Minus operators are the set operators used in the SQL. In SQL, set operators are used to combine the results of two or more SELECT statements. The commonly used set operators are: UNION: Returns the combined result set of two … Read more

A self-join is often very useful to convert a hierarchical structure to a flat structure. It is used to join a table to itself as like if that is the second table. In SQL, a self-join is a regular join, but the table is joined with itself. This can be useful when you want to … Read more

A trigger allows you to execute a batch of SQL code when an insert, update or delete command is run against a specific table as TRIGGER is said to be the set of actions that are performed whenever commands like insert, update or delete are given through queries. The trigger is said to be activated … Read more

Full join return rows when there are matching rows in any one of the tables. This means it returns all the rows from the left-hand side table and all the rows from the right-hand side table. In SQL, there is no specific “FULL JOIN” keyword. However, you can achieve a full join using a combination … Read more

The left join is used to retrieve rows which are common between the tables and all rows of the Left-hand side table. It returns all the rows from the Left-hand side table even though there are no matches on the Right-hand side table. A Left Join in SQL is a type of join operation that … Read more