Does an SQL query like this exist? - php

Question

I found something on google which said MySql allows me to do something like this:
$sql = "IF(EXISTS(SELECT api_key, username FROM credentials WHERE id = 0))
THEN UPDATE credentials SET api_key = ?, username = ? WHERE id = 0 ELSE
INSERT INTO credentials (api_key, username) VALUES (?, ?) END IF";
This is the function the query makes part of:
protected function store_credentials($config_file_path = 'envato_credentials_config.json') {
$credentials_config = $this->get_envato_config($config_file_path);
$sql = "INSERT INTO credentials (api_key, username, last_update) VALUES (?, ?, NOW()) ON DUPLICATE KEY UPDATE api_key = values(api_key), username = values(username), last_update = values(last_update)";
if ($stmt = $this->connect->prepare($sql)) {
$stmt->bind_param('ss', $credentials_config['API'], $credentials_config['User']);
$stmt->execute();
$stmt->close();
} else {
return false;
}
}
Can I do something like that ? And am I understanding the statement clearly, if no values are found inside those two columns then new values will be inserted, else it will only update ?

Answer 1

You could use MySQL's on duplicate key syntax:
INSERT INTO credentials (api_key, username) VALUES (?, ?)
ON DUPLICATE KEY UPDATE api_key = values(api_key), username = values(username);

Answer 2

mysql has REPLACE syntax which does this. If record exists it updates it (actually deletes old row and inserts new row) otherwise inserts.
http://dev.mysql.com/doc/refman/5.0/en/replace.html
13.2.7. REPLACE Syntax
REPLACE [LOW_PRIORITY | DELAYED]
[INTO] tbl_name [(col_name,...)]
{VALUES | VALUE} ({expr | DEFAULT},...),(...),...
Or:
REPLACE [LOW_PRIORITY | DELAYED]
[INTO] tbl_name
SET col_name={expr | DEFAULT}, ...
Or:
REPLACE [LOW_PRIORITY | DELAYED]
[INTO] tbl_name [(col_name,...)]
SELECT ...
REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted. See Section 13.2.5, “INSERT Syntax”.
REPLACE is a MySQL extension to the SQL standard. It either inserts, or deletes and inserts. For another MySQL extension to standard SQL—that either inserts or updates—see Section 13.2.5.3, “INSERT ... ON DUPLICATE KEY UPDATE Syntax”.
Note that unless the table has a PRIMARY KEY or UNIQUE index, using a REPLACE statement makes no sense. It becomes equivalent to INSERT, because there is no index to be used to determine whether a new row duplicates another.
Values for all columns are taken from the values specified in the REPLACE statement. Any missing columns are set to their default values, just as happens for INSERT. You cannot refer to values from the current row and use them in the new row. If you use an assignment such as SET col_name = col_name + 1, the reference to the column name on the right hand side is treated as DEFAULT(col_name), so the assignment is equivalent to SET col_name = DEFAULT(col_name) + 1.
To use REPLACE, you must have both the INSERT and DELETE privileges for the table.