Tag Archives: CodeProject

Difference between Subquery, Nested Subquery and Correlated Subquery

Posted on September 29, 2009 by vivekjohari

Difference between Subquery, Nested Subquery and Correlated Subquery Query Query can be defined as a way to inquire the data from the database. It is used to extract the data from one table or multiple tables depending upon the user … Continue reading →

Posted in Interview Questions, Most Imp SQL Concepts, SQL Queries Sub-queries, SQL Server | Tagged , , | 102 Comments

Sql server Constraints – Primary Key, Foreign Key, Unique Key, Not Null, Check Constraints

Posted on August 19, 2009 by vivekjohari

Introduction A constraint is a property that is assigned to a column or a group of columns to prevent incorrect or corrupt data from entering into the tables. These constraints ensure the accuracy and reliability of the data into the … Continue reading →

Posted in Most Imp SQL Concepts, SQL Primary Key Constraint, SQL Server | Tagged , , , | 31 Comments