function db_distinct_field

6.x database.inc db_distinct_field($table, $field, $query)

Adds the DISTINCT flag to the supplied query and returns the altered query.

The supplied query should not contain a DISTINCT flag. This will not, and never did guarantee that you will obtain distinct values of $table.$field.

Parameters

$table: Unused. Kept to retain API compatibility.

$field: Unused. Kept to retain API compatibility.

$query: Query to which the DISTINCT flag should be applied.

Return value

SQL query with the DISTINCT flag set.

Related topics

Database abstraction layer: Allow the use of different database servers using the same code base.

1 call to db_distinct_field()

db_rewrite_sql in drupal-6.x/includes/database.inc: Rewrites node, taxonomy and comment queries. Use it for listing queries. Do not use FROM table1, table2 syntax, use JOIN instead.

File

drupal-6.x/includes/database.inc, line 407: Wrapper for database interface code.

Code

function db_distinct_field($table, $field, $query) {
  $matches = array();
  if (!preg_match('/^SELECT\s*DISTINCT/i', $query, $matches)) {
    // Only add distinct to the outer SELECT to avoid messing up subqueries.
    $query = preg_replace('/^SELECT/i', 'SELECT DISTINCT', $query);
  }

  return $query;
}