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Constraints are the rules and regulations which are applied to the table column which enforces yours to store valid data and prevents users to store irrelevant data. There are two levels : column level constraint table level constraint In SQL, a constraint is a rule or condition that is enforced on data in a table. … Read more

The BETWEEN operator is used to display rows based on a range of values. The values can be numbers, text, and dates as well. BETWEEN operator gives us the count of all the values occurs between a particular range. The IN condition operator is used to check for values contained in a specific set of … Read more

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