MySQL: Insert record if not exists in table

MySQL provides a very cute solution :

REPLACE INTO `table` VALUES (5, 'John', 'Doe', SHA1('password'));

Very easy to use since you have declared a unique primary key (here with value 5).

I'm not actually suggesting that you do this, as the UNIQUE index as suggested by Piskvor and others is a far better way to do it, but you can actually do what you were attempting:

CREATE TABLE `table_listnames` (
  `id` int(11) NOT NULL auto_increment,
  `name` varchar(255) NOT NULL,
  `address` varchar(255) NOT NULL,
  `tele` varchar(255) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB;

Insert a record:

INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Rupert', 'Somewhere', '022') AS tmp
WHERE NOT EXISTS (
    SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;

Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

SELECT * FROM `table_listnames`;

+----+--------+-----------+------+
| id | name   | address   | tele |
+----+--------+-----------+------+
|  1 | Rupert | Somewhere | 022  |
+----+--------+-----------+------+

Try to insert the same record again:

INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Rupert', 'Somewhere', '022') AS tmp
WHERE NOT EXISTS (
    SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;

Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0

+----+--------+-----------+------+
| id | name   | address   | tele |
+----+--------+-----------+------+
|  1 | Rupert | Somewhere | 022  |
+----+--------+-----------+------+

Insert a different record:

INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'John', 'Doe', '022') AS tmp
WHERE NOT EXISTS (
    SELECT name FROM table_listnames WHERE name = 'John'
) LIMIT 1;

Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

SELECT * FROM `table_listnames`;

+----+--------+-----------+------+
| id | name   | address   | tele |
+----+--------+-----------+------+
|  1 | Rupert | Somewhere | 022  |
|  2 | John   | Doe       | 022  |
+----+--------+-----------+------+

And so on...

---

Update:

To prevent #1060 - Duplicate column name error in case two values may equal, you must name the columns of the inner SELECT:

INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Unknown' AS name, 'Unknown' AS address, '022' AS tele) AS tmp
WHERE NOT EXISTS (
    SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;

Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

SELECT * FROM `table_listnames`;

+----+---------+-----------+------+
| id | name    | address   | tele |
+----+---------+-----------+------+
|  1 | Rupert  | Somewhere | 022  |
|  2 | John    | Doe       | 022  |
|  3 | Unknown | Unknown   | 022  |
+----+---------+-----------+------+

INSERT doesn't allow WHERE in the syntax.

What you can do: create a UNIQUE INDEX on the field which should be unique (name), then use either:

• normal INSERT (and handle the error if the name already exists)
• INSERT IGNORE (which will fail silently cause a warning (instead of error) if name already exists)
• INSERT ... ON DUPLICATE KEY UPDATE (which will execute the UPDATE at the end if name already exists, see documentation)

Worked :

INSERT INTO users (full_name, login, password) 
  SELECT 'Mahbub Tito','tito',SHA1('12345') FROM DUAL
WHERE NOT EXISTS 
  (SELECT login FROM users WHERE login='tito');