Query in MySQL for string fields with a specific length?

MySQLMySQLi Database

To query for string fields with a specific length, use the char_length() or length() from MySQL.

Syntax

The syntax is as follows −

Case 1 − Use of char_length()

This can be used when we are taking length in a number of characters.

The syntax −

select *from yourTableName where
char_length(yourColumnName)=anySpecificLengthValue;

Case 2 − Use of length()

This can be used when we are taking the length in bytes.

The syntax −

select *from yourTableName where length(yourColumnName)=anySpecificLengthValue;

To understand the above concept, let us first create a table. The query to create a table is as follows −

mysql> create table StringWithSpecificLength
-> (
-> Id int,
-> Name varchar(100),
-> FavouriteLanguage varchar(50)
-> );
Query OK, 0 rows affected (0.52 sec)

Insert records in the table using insert command. The query is as follows −

mysql> insert into StringWithSpecificLength values(1,'John','Java');
Query OK, 1 row affected (0.66 sec)

mysql> insert into StringWithSpecificLength values(2,'Bob','PHP');
Query OK, 1 row affected (0.17 sec)

mysql> insert into StringWithSpecificLength values(3,'Carol','Python');
Query OK, 1 row affected (0.16 sec)

mysql> insert into StringWithSpecificLength values(4,'Sam','Ruby');
Query OK, 1 row affected (0.25 sec)

mysql> insert into StringWithSpecificLength values(5,'Mike','Pascal');
Query OK, 1 row affected (0.19 sec)

Display all records from the table using a select statement. The query is as follows −

mysql> select *from StringWithSpecificLength;

Output

+------+-------+-------------------+
| Id   | Name  | FavouriteLanguage |
+------+-------+-------------------+
|    1 | John  | Java              |
|    2 | Bob   | PHP               |
|    3 | Carol | Python            |
|    4 | Sam   | Ruby              |
|    5 | Mike  | Pascal            |
+------+-------+-------------------+
5 rows in set (0.00 sec)

The following is the query to fetch string fields with specific length −

mysql> select *from StringWithSpecificLength where char_length(FavouriteLanguage)=6;

Output

+------+-------+-------------------+
| Id    | Name | FavouriteLanguage |
+------+-------+-------------------+
| 3    | Carol | Python            |
| 5    | Mike  | Pascal            |
+------+-------+-------------------+
2 rows in set (0.00 sec)
raja
Published on 10-Jan-2019 10:26:14
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