SQL Constraints
SQL constraints are set set of rules by which SQL engine enforces the integrity of database. Constraint maintains the standard rules to follow so that integrity in database can be maintained. If there is...
Category: SQL Commands
Use DBCC CHECKIDENT to RESEED Table Identity Columns
In many tables we use Identity column to maintain the uniqueness and automatically increment the values when records are inserted. If you want to reset the identity column numbers in a table then we...
SQL PRIMARY KEY Constraint
SQL PRIMARY KEY constraint uniquely identifies each row in a database table. A primary key column cannot have NULL values. A table can have only one primary key with single or multiple fields. Primary...
SQL UNION ALL Operator
SQL UNION ALL operator is used to combine the results of two or more SELECT statements. Each SELECT statement within the UNION ALL must have the same number of columns and all columns should have...
SQL UNION Operator
SQL UNION operator is used to combine the results of two or more SELECT statements. Each SELECT statement within the UNION must have the same number of columns and all columns should have same order...
SQL CROSS JOIN
SQL CROSS JOIN returns all records where each row from the first table is combined with each row of the second table. CROSS JOIN returns the Cartesian product of the tables involved in join if...
