What is “SELECT TRUE” in MySQL?

The statement SELECT TRUE returns 1 if a row match. Let us first create a table −

mysql> create table DemoTable(Name varchar(100));
Query OK, 0 rows affected (0.54 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('Chris');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('Robert');
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values('David');
Query OK, 1 row affected (0.12 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+--------+
| Name   |
+--------+
| Chris  |
| Robert |
| David  |
+--------+
3 rows in set (0.00 sec)

Following is the query for SELECT TRUE −

mysql> select true from DemoTable;

This will produce the following output −

+------+
| TRUE |
+------+
| 1    |
| 1    |
| 1    |
+------+
3 rows in set (0.00 sec)