SQL - Like Operator

The SQL LIKE Operator

TheSQL LIKEoperator is used to search for a specified pattern in a column. It is often used in the WHERE clause of the SELECT, UPDATE, or DELETE statements to filter results based onwildcard patterns.

Suppose we need to submit the list of all the students whose name starts with ‘K’. We can obtain this with the help of the LIKE operator as follows:

WHERE student_name LIKE 'K%';

Here,

• %is a wildcard representing zero or more characters.
• K%specifies that it will display the list of all the students whose namestarts with’k’.

The LIKE operator can be used with strings, numbers, or date values. However, using the string values is recommended.

Syntax

The basic syntax of the SQL LIKE operator is as follows:

SELECT column1, column2, ...
FROM table_name
WHERE columnn LIKE specified_pattern;

SQL Wildcards in LIKE Operator

SQL wildcards are special characters used in SQL queries to match patterns in the data.

Following are the two most common wildcards used in conjunction with the LIKE operator in MySQL database:

S.NoWildCard & Definition1%The percent sign represents zero, one or multiple characters.2_The underscore represents a single number or character.

In the LIKE operator, the above wildcard characters can be used individually as well as in combinations with each other.

Examples

The table given below has a few examples showing the WHERE clause having different LIKE operators with ’%’ and ’_‘:

S.NoStatement & Description1WHERE SALARY LIKE ‘200%‘Finds any values that start with 200.2WHERE SALARY LIKE ‘%200%‘Finds any values that have 200 in any position.3WHERE SALARY LIKE ‘00%‘Finds any values that have 00 in the second and third positions.4WHERE SALARY LIKE ‘2%_%‘Finds any values that start with 2 and are at least 3 characters in length.5WHERE SALARY LIKE ‘%2’Finds any values that end with 2.6WHERE SALARY LIKE ‘_2%3’Finds any values that have a 2 in the second position and end with a 3.7WHERE SALARY LIKE ‘2___3’Finds any values in a five-digit number that start with 2 and end with 3.

Using % Wildcard in SQL LIKE

The % sign represents zero or multiple characters. The ’%’ wildcard matches any length of a string which even includes the zero length.

Example: Find salaries starting with 200

To understand it better let us consider the CUSTOMERS table which contains the personal details of customers including their name, age, address and salary etc. as shown below:

CREATE TABLE CUSTOMERS (
   ID INT NOT NULL,
   NAME VARCHAR (20) NOT NULL,
   AGE INT NOT NULL,
   ADDRESS CHAR (25),
   SALARY DECIMAL (18, 2),       
   PRIMARY KEY (ID)
);

Now, insert values into this table using the INSERT statement as follows:

INSERT INTO CUSTOMERS VALUES 
(1, 'Ramesh', 32, 'Ahmedabad', 2000.00 ),
(2, 'Khilan', 25, 'Delhi', 1500.00 ),
(3, 'Kaushik', 23, 'Kota', 2000.00 ),
(4, 'Chaitali', 25, 'Mumbai', 6500.00 ),
(5, 'Hardik', 27, 'Bhopal', 8500.00 ),
(6, 'Komal', 22, 'Hyderabad', 4500.00 ),
(7, 'Muffy', 24, 'Indore', 10000.00 );

The table will be created as follows:

IDNAMEAGEADDRESSSALARY1Ramesh32Ahmedabad2000.002Khilan25Delhi1500.003Kaushik23Kota2000.004Chaitali25Mumbai6500.005Hardik27Bhopal8500.006Komal22Hyderabad4500.007Muffy24Indore10000.00

Now, let us display all the records from the CUSTOMERS table, where the SALARY starts with 200:

SELECT * FROM CUSTOMERS WHERE SALARY LIKE '200%';

This would produce the following result:

IDNAMEAGEADDRESSSALARY1Ramesh32Ahmedabad2000.003Kaushik23Kota2000.00

Example: Find names ending with “sh”

The following query finds rows where the NAME ends withsh:

SELECT * FROM CUSTOMERS WHERE NAME LIKE '%sh';

This produces the following output:

IDNAMEAGEADDRESSSALARY1Ramesh32Ahmedabad2000.00

Example: Find names containing “al”

Below is the query that displays all the records from the CUSTOMERS table previously created with the NAME that has ‘al’ in any position. Here, we are using multiple ’%’ wildcards in the LIKE condition:

SELECT * FROM CUSTOMERS WHERE NAME LIKE '%al%';

The following result is produced:

IDNAMEAGEADDRESSSALARY4Chaitali25Mumbai6500.006Komal22Hyderabad4500.00

Using _ Wildcard in SQL LIKE

Theunderscore ()wild card represents a single number or character. A single '' looks for exactly one character similar to the ’%’ wildcard.

Example: Names starting with K and at least 4 characters long

Following is the query which would display all the records from the CUSTOMERS table previously created, where the Name starts withKand is at least 4 characters in length:

SELECT * FROM CUSTOMERS WHERE NAME LIKE 'K___%';

The result obtained is given below:

IDNAMEAGEADDRESSSALARY2Khilan25Delhi1500.003Kaushik23Kota2000.006Komal22Hyderabad4500.00

Example: Names with “m” in the third position

Following is the query to display all the records from the CUSTOMERS table, where the NAME has ‘m’ in the third position:

SELECT * FROM CUSTOMERS WHERE NAME LIKE '__m%';

We get the following result on executing the above query:

IDNAMEAGEADDRESSSALARY1Ramesh32Ahmedabad2000.006Komal22Hyderabad4500.00

Combining Wildcards in SQL LIKE

You can combine%and_wildcards to create more precise patterns. The underscore_matches exactly one character, while%matches zero or more characters.

Below are some patterns with their meanings in brief:

PatternDescription’K___%‘Name starts with K, followed by at least three characters, then any number of characters.’_2%3’Any first character, second character is 2, ends with 3.‘2___3’Five-character value starting with 2 and ending with 3.

Combining wildcards is useful when you know the approximate length or specific characters at certain positions but want to allow different characters in other places.

SQL LIKE with OR

We can also use the LIKE operator with multiple string patterns for selecting rows by using theANDorORoperators.

Syntax

Following is the basic syntax of using LIKE operator with OR operator:

SELECT column1, column2, ...
FROM table_name
WHERE column1 LIKE pattern1 OR column2 LIKE pattern2 OR ...;

Example

Here, the SQL query retrieves the records of the customers whose name starts withCand ends withi, or customers whose name ends withk:

SELECT * FROM CUSTOMERS WHERE NAME LIKE 'C%i' OR NAME LIKE '%k';

This will produce the following result:

IDNAMEAGEADDRESSSALARY3Kaushik23Kota2000.004Chaitali25Mumbai6500.005Hardik27Bhopal8500.00

SQL NOT LIKE

We use the NOT operator with LIKE to extract the rows which does not contain a particular string provided in the search pattern.

Syntax

Following is the basic syntax of NOT LIKE operator in SQL:

SELECT column1, column2, ...
FROM table_name
WHERE column1 NOT LIKE pattern;

Example

In the query given below, we are fetching all the customers whose name does not start withK:

SELECT * FROM CUSTOMERS WHERE NAME NOT LIKE 'K%';

This will produce the following result:

IDNAMEAGEADDRESSSALARY1Ramesh32Ahmedabad2000.004Chaitali25Mumbai6500.005Hardik27Bhopal8500.007Muffy24Indore10000.00

Escape Characters in SQL LIKE

The escape character in SQL is used to exclude certain wildcard characters from the expression of theLIKEoperator. By doing so, we can use these characters in their general sense.

Using the escape character, we can also avoid using the characters that are reserved in SQL syntax to denote specific commands, such as the single quote’,%and_.

For example, if you need to search for%as a literal in the LIKE condition, then it is done using Escape character.

An escape character is only defined as a single character. It is suggested to choose the character which is not present in our data.

Syntax

The syntax for using the LIKE operator with escape characters is as follows:

SELECT column1, column2, ...
FROM table_name
WHERE column1 LIKE 'pattern ESCAPE escape_character';

Where,

• patternis the pattern you want to match.
• ESCAPEis the keyword that indicates the escape character
• escape_characteris the character that you want to use as the escape character.

Example: Find values containing literal %

Let us create a new table EMPLOYEE using the query below:

CREATE TABLE EMPLOYEE (
   SALARY DECIMAL (18,2) NOT NULL,
   BONUS_PERCENT VARCHAR (20)
);

Now, we can insert values into this empty tables using the INSERT statement as follows:

INSERT INTO EMPLOYEE VALUES 
(67000.00, '45.00'),
(54000.00, '20.34%'),     
(75000.00, '51.00'),        
(84000.00, '56.82%');

TheEmployeetable consists of the salary of employees in an organization and the bonus percentage in their salary as shown below:

SALARYBONUS_PERCENT67000.0045.0054000.0020.34%75000.0051.0084000.0056.82%

Now, we are displaying all the records from the EMPLOYEE table, where the BONUS_PERCENT contains the%literal:

SELECT * FROM EMPLOYEE 
WHERE BONUS_PERCENT LIKE'%!%%' ESCAPE '!';

This will produce the following result:

SALARYBONUS_PERCENT54000.0020.34%84000.0056.82%

Example: Find values starting with 2 and containing %

In here, we are retrieving the BONUS_PERCENT that starts with2and contains the%literal:

SELECT * FROM EMPLOYEE 
WHERE BONUS_PERCENT LIKE'2%!%%' ESCAPE '!';

Following result is obtained:

SALARYBONUS_PERCENT54000.0020.34%

SQL LIKE Without Using Wildcards

When theLIKEoperator is used without any wildcards, it behaves like the=operator and matches the value exactly. This is sometimes done to make the pattern clearer or to allow adding wildcards later.

Syntax

Following is the syntax to use the SQL LIKE operator without using wildcards:

SELECT column1, column2, ...
FROM table_name
WHERE column_name LIKE 'exact_value';

Example: Exact match for “Komal”

SELECT * FROM CUSTOMERS WHERE NAME LIKE 'Komal';

This returns only the rows where NAME is exactlyKomal:

IDNAMEAGEADDRESSSALARY6Komal22Hyderabad4500.00

Common Uses of SQL LIKE Operator

The few uses of LIKE operators are given below:

• It helps us to extract data that matches with the required pattern.
• It helps us in performing complex regex-based queries on our data.
• It simplifies the complex queries.