public function SelectQuery_sqlsrv::__toString in Drupal driver for SQL Server and SQL Azure 7

Same name and namespace in other branches

1. 7.3 sqlsrv/select.inc \SelectQuery_sqlsrv::__toString()
2. 7.2 sqlsrv/select.inc \SelectQuery_sqlsrv::__toString()

Implements PHP magic __toString method to convert the query to a string.

The toString operation is how we compile a query object to a prepared statement.

Return value

A prepared statement query string for this object.

Overrides SelectQuery::__toString

File

sqlsrv/select.inc, line 73

Class

SelectQuery_sqlsrv

Code

public function __toString() {

  // For convenience, we compile the query ourselves if the caller forgot
  // to do it. This allows constructs like "(string) $query" to work. When
  // the query will be executed, it will be recompiled using the proper
  // placeholder generator anyway.
  if (!$this
    ->compiled()) {
    $this
      ->compile($this->connection, $this);
  }

  // Create a sanitized comment string to prepend to the query.
  $comments = $this->connection
    ->makeComment($this->comments);

  // SELECT
  $query = $comments . 'SELECT ';
  if ($this->distinct) {
    $query .= 'DISTINCT ';
  }

  // FIELDS and EXPRESSIONS
  $fields = array();
  foreach ($this->tables as $alias => $table) {
    if (!empty($table['all_fields'])) {
      $fields[] = $this->connection
        ->escapeTable($alias) . '.*';
    }
  }
  foreach ($this->fields as $alias => $field) {

    // Always use the AS keyword for field aliases, as some
    // databases require it (e.g., PostgreSQL).
    $fields[] = (isset($field['table']) ? $this->connection
      ->escapeTable($field['table']) . '.' : '') . $this->connection
      ->escapeField($field['field']) . ' AS ' . $this->connection
      ->escapeField($field['alias']);
  }
  foreach ($this->expressions as $alias => $expression) {
    $fields[] = $expression['expression'] . ' AS ' . $expression['alias'];
  }
  $query .= implode(', ', $fields);

  // FROM - We presume all queries have a FROM, as any query that doesn't won't need the query builder anyway.
  $query .= "\nFROM ";
  foreach ($this->tables as $alias => $table) {
    $query .= "\n";
    if (isset($table['join type'])) {
      $query .= $table['join type'] . ' JOIN ';
    }

    // If the table is a subquery, compile it and integrate it into this query.
    if ($table['table'] instanceof SelectQueryInterface) {

      // Run preparation steps on this sub-query before converting to string.
      $subquery = $table['table'];
      $subquery
        ->preExecute();
      $table_string = '(' . (string) $subquery . ')';
    }
    else {
      $table_string = '{' . $this->connection
        ->escapeTable($table['table']) . '}';
    }

    // Don't use the AS keyword for table aliases, as some
    // databases don't support it (e.g., Oracle).
    $query .= $table_string . ' ' . $this->connection
      ->escapeTable($table['alias']);
    if (!empty($table['condition'])) {
      $query .= ' ON ' . $table['condition'];
    }
  }

  // WHERE
  if (count($this->where)) {

    // There is an implicit string cast on $this->condition.
    $query .= "\nWHERE ( " . $this->where . " )";
  }

  // GROUP BY
  if ($this->group) {
    $query .= "\nGROUP BY " . implode(', ', $this->group);
  }

  // HAVING
  if (count($this->having)) {

    // There is an implicit string cast on $this->having.
    $query .= "\nHAVING " . $this->having;
  }

  // ORDER BY
  // The ORDER BY clause is invalid in views, inline functions, derived
  // tables, subqueries, and common table expressions, unless TOP or FOR XML
  // is also specified.
  if ($this->order && (empty($this->inSubQuery) || !empty($this->range))) {
    $query .= "\nORDER BY ";
    $fields = array();
    foreach ($this->order as $field => $direction) {
      $fields[] = $field . ' ' . $direction;
    }
    $query .= implode(', ', $fields);
  }

  // RANGE
  if (!empty($this->range)) {
    $query = $this->connection
      ->addRangeToQuery($query, $this->range['start'], $this->range['length']);
  }

  // UNION is a little odd, as the select queries to combine are passed into
  // this query, but syntactically they all end up on the same level.
  if ($this->union) {
    foreach ($this->union as $union) {
      $query .= ' ' . $union['type'] . ' ' . (string) $union['query'];
    }
  }
  return $query;
}