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How to check if value exists with MySQL SELECT 1?
Use SELECT 1 for this as in the below syntax −
select 1 from yourTableName where yourColumnName=yourValue;
If the above returns 1, that means value exists in the MySQL database. Let us first see an example and create a table −
mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(40), StudentAge int ); Query OK, 0 rows affected (0.46 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable(StudentName,StudentAge) values('Chris',21);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('David',20);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('Bob',22);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable(StudentName,StudentAge) values('Tom',19);
Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-----------+-------------+------------+ | StudentId | StudentName | StudentAge | +-----------+-------------+------------+ | 1 | Chris | 21 | | 2 | David | 20 | | 3 | Bob | 22 | | 4 | Tom | 19 | +-----------+-------------+------------+ 4 rows in set (0.00 sec)
Let us now check if value exists in MySQL database −
mysql> select 1 from DemoTable where StudentName='Bob';
This will produce the following output −
+---+ | 1 | +---+ | 1 | +---+ 1 row in set (0.00 sec)
Updated on: 07-Oct-2019
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