How can I check if mysql table column even exists?

Question

How can I check if mysql table field even exists ?

The column name is \'price\' and I need to see if it exists.

Haven\'t understood really how the \'EXISTS\'

Answer 1

I just done something like this using this function for Wordpress, this for update tables that having new chnages on it

public function alterTable() {

    $table_name = $this->prefix . $this->tables['name'];

    $select = "select * from `{$table_name}` where 0=0 limit 1;";
    $query = $this->db->get_results($select, ARRAY_A);


    if (isset($query[0]) && !key_exists('adv', $query[0])) {
        $sql = "ALTER TABLE `{$table_name}` ADD `me` INT NULL DEFAULT NULL ;";
        $this->db->query($sql);
    }

}

Answer 2

well here is a function to check out if a particular column exists or not.

public function detect_column($my_db, $table, $column)
{
    $db = mysql_select_db($my_db); //select the database
    $sql = "SHOW COLUMNS FROM $table LIKE '$column'"; //query
    $result = mysql_query($sql);                     //querying
    if(mysql_num_rows($result) == 0)        //checks the absence of column
        echo "column $column doesn't exist !";
        // write your code here! 
    else
        echo "column $column exists!";
}

well if you are designing a frame work, then this function may come to your aid. This function checks for the presence of column when $flag is set to '1' and absence of column when $flag is set to '0'.

public function detect_column($my_db, $table, $column, $flag)
{
    $this->select_db($my_db); //select the database
    $sql = "SHOW COLUMNS FROM $table LIKE '$column'";
    $result = mysql_query($sql);
    if(mysql_num_rows($result) == $flag)
        return true;
    else
        return false;
}