MySQL Where Clause
A WHERE Clause is an SQL query to apply a filter on the rows retrieved.
When a WHERE Clause is added to MySQL query, the MySQL engine compares each record in the table with the condition specified in the WHERE Clause.The MySQL engine display only those records that satisfy the specified condition.
Syntax:
|
1 |
SELECT * FROM tablename where condition; |
MySQL table(tblemployee)
| id | Emp_Name | Emp_Code | Emp_Designation | Emp_joinnig_date |
|---|---|---|---|---|
| 1 | Anuj Kumar | 10806121 | Software Developer | 2018-02-01 |
| 1 | Sanjeev Kumar | 10806860 | Software Testing | 2015-10-15 |
| 1 | Rahul Singh | 10806865 | HR | 2016-12-22 |
| 1 | John Doe | 13406121 | Accountant | 2019-03-01 |
Ex:
|
1 |
Select Emp_Name from tblemployee where id=1; |
Output
Anuj Kumar
Operators in the where clause :
| Operator | Description |
|---|---|
| = | Equality |
| != | Inequality |
| < | Less than |
| <= | Less than or equal |
| > | More than |
| >= | More than or equal |
| Between min | Within the range |
| AND max | min to max |
| IS NULL | Is a NULL Value |
| IS NOT NULL | Is not a null value |
Comparison operators are used in a query with a WHERE clause to test if a specified condition is met. When the evaluation is TRUE the query will return the data, otherwise nothing will be returned.
MySQL 5.6 reference manual online at dev.mysql.com/doc
