How to Use Comparison Operators to Specify Conditions: SQL Programming

December 12, 2013 , , 0 Comments

Comparison operators test whether two expressions are same or not. These operators can be used on all the sql data types except some of them like text, ntext or image. Equal to, greater then, less than are such operators. The article will let you enable to use these operators with examples.

While arithmetic operators are used to calculate column values, Comparison operators test for similarity between two expressions. You can create conditions in the SELECT statement to retrieve selected rows by using various comparison operators. Comparison operators allow row retrieval from a table based on the condition specified in the WHERE clause. Comparison operators cannot be used on text, ntext, or image data type expressions.
The syntax for using the comparison operator in the SELECT statement is:

 SELECT column_list
 FROM table_name
 WHERE expressiona1 comparison_operator expression2

  • column_list: list of fields to be shown in output.
  • table_name: from the records are to be retrieved.
  • expression1 and expression2: any expression on which the operator will be applied.
  • comparison_operator: may be one listed below.
The following SQL query retrieves records from the Employee table where the vacation hour is more than 20:
SELECT BusinessEntityID, NationalIDNumber, JobTitle, VacationHours FROM HumanResources.Employee WHERE VacationHours > 20

In the preceding example, the query retrieves all the rows that satisfy the specified condition by using the comparison operator. The result is shown in the following image:

How to Use Comparison Operators to Specify Conditions: SQL Programming

The SQL Server provides the following comparison operators.
  • =   Equal to
  • >   Greater than
  • <   Less than
  • >=   Greater than or equal to
  • <=   Less than or equal to
  • <>   Not equal to
  • !=   Not equal to
  • !<   Not less than
  • !>   Not greater than
Sometimes, you might need to view records for which one or more conditions hold true. Depending on the requirements, you can retrieve records based on the following conditions:

Rhett Butler

Some say he’s half man half fish, others say he’s more of a seventy/thirty split. Either way he’s a fishy bastard. Google