How to Check if value exists in a MySQL database

Question

Suppose I have this table:

id | name | city ------------------ 1  | n1   | c1 2  | n2   | c2 3  | n3   | c3 4  | n4   | c4 

I want to check if the value c7 exists under the variable city or not.

If it does, I will do something.
If it doesn't, I will do something else.

Answer 1

preferred way, using MySQLi extension:

$mysqli = new mysqli(SERVER, DBUSER, DBPASS, DATABASE); $result = $mysqli->query("SELECT id FROM mytable WHERE city = 'c7'"); if($result->num_rows == 0) {      // row not found, do stuff... } else {     // do other stuff... } $mysqli->close(); 

deprecated:

$result = mysql_query("SELECT id FROM mytable WHERE city = 'c7'"); if(mysql_num_rows($result) == 0) {      // row not found, do stuff... } else {     // do other stuff... } 

Answer 2

For Exact Match

"SELECT * FROM yourTable WHERE city = 'c7'" 

For Pattern / Wildcard Search

"SELECT * FROM yourTable WHERE city LIKE '%c7%'" 

Of course you can change '%c7%' to '%c7' or 'c7%' depending on how you want to search it. For exact match, use first query example.

PHP

$result = mysql_query("SELECT * FROM yourTable WHERE city = 'c7'"); $matchFound = mysql_num_rows($result) > 0 ? 'yes' : 'no'; echo $matchFound; 

You can also use if condition there.