Question

I have a function that accepts an array of tables as the parameter and after inner joining them returns the resulted rows.

function myfunc($tables, $join_on) {
 foreach($tables as $table) {
  // build query
 }
}

How do I build the query? for example if $tables = array('table1', 'table2') and $join_on = 'field_x' then it should create the following query:

SELECT * FROM table1 INNER JOIN table2 ON table1.field_x = table2.field_x

Answer 1

You can do something like this :

function myfunc($tables, $join_on) {
    $mainTable = $tables[0];
    $sql = "SELECT * FROM $mainTable";
    for($i = 1; i<count($tables);$i++) {
        $curTable = $tables[$i];
        $joinField = $join_on[$i-1];
        $sql.= " INNER JOIN $curTable ON $curTable.$joinField = $mainTable.$joinField";
    }

    return sql;
}

Of course you need to add some error checking to ensure that you have at least one table in $tables and always N-1 elements in $join_on where N is the number of tables in $tables