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SQL WHERE Clause

  • The WHERE clause is used to explicitly filter out only those records that meet the conditions specified by you. This saves time, effort and complexity.
  • Using the WHERE clause makes specified data aggregation a lot easier
  • In fetching these relational data items, the WHERE clause in SQL is used. This is responsible for selecting only those data items that correspond to the mentioned conditions.
  • This is done to specifically filter out particular columns.

Syntax:

SELECT column_ name
FROM table_ name
WHERE condition;
  • Operators in the WHERE Clause help you to specify the various conditions that you would like to query from a database.

Operators used in WHERE to select desired columns for a record are:


Examples of WHERE Clause Operators:

Let's consider an EMPLOYEES table containing information on employees working in a firm distributed across India.

IDNAMEAGEADDRESSSALARY
1Shweta25MumbaiRs 12000
2Raj26GoaRs 25000
3Abhi30KarnatakaRs 18000
4Roshani32KeralaRs 15000

Example:

1. Where Clause with the EQUAL Operator:

This is used to display only those records which have values equal to the values specified.

Example:

SELECT ID, NAME
FROM EMPLOYEES
WHERE AGE=32;
  • Above, the code is used to fetch the ID and NAME values for those employees wherein the age of the employee is equal to 32 

Output:

From the table, you can see that employee Roshani meets the given criteria.


2. WHERE Clause with the LESS THAN and GREATER THAN Operators:

These shall be used to display only those records that have values lesser than and greater than the values specified respectively.

Example:

SELECT ID, NAME
FROM EMPLOYEES
WHERE SALARY <20000;
  • Above, the code is used to fetch the ID and NAME values for those employees wherein the salaries of the employees are less than Rs. 20000.

Output:

From the table, you can see that employees Seema Kapoor and Abhi Kumar meet the given criterion.