SQL Like Query
For wildcard filtering “Like ” operator is used. Within a search string, % means match any number of occurrences of any character. For example, to fetch all the employees starting with letter "J" from employee table given below, following SQL query is used.
Table Name: Employee
| Employee_ID | Employee_Name | Age |
|---|---|---|
| 1 | John | 28 |
| 2 | Alex | 24 |
| 3 | James | 35 |
| 4 | Roy | 22 |
| 5 | Kay | 44 |
select * from employee where employee_name like 'J%'
The result of the above given query is given below.
| mployee_ID | Employee_Name | Age |
|---|---|---|
| 1 | John | 28 |
| 3 | James | 35 |
To fetch all names containing letter a, following SQL query is used. This query will fetch all records having letter 'a' at any position. Please note that, like query is case sensitive.
select * from employee where employee_name like '%a%'
| Employee_ID | Employee_Name | Age |
|---|---|---|
| 3 | James | 35 |
| 5 | Kay | 44 |
To fetch all names ending with letter y, following SQL query is used.
select * from employee where employee_name like '%y'
| Employee_ID | Employee_Name | Age |
|---|---|---|
| 4 | Roy | 22 |
| 5 | Kay | 44 |
Points to be noted before using Like Operator
SQL 'Like' search takes more time to process. So before using like operator following tips should be considered.
- Don't overuse wildcards. If another search operator will do, use it instead.
- When you do use wildcards, try to not use them at the beginning of the search pattern unless absolutely necessary. Search patterns that begin with wildcards are the slowest to process.
- Pay careful attention to the placement of the wildcard symbols. If they are misplaced, you might not return the data you intended.
