1

これは多かれ少なかれ、このHow to preserve the order of fields to be selected when using $query->addExpression() に関連しています。

私がやっていることはunion、複数のテーブルを作成することです。ただし、値がどのテーブルから取得されているかを知る必要もあります。だから私はちょうどこのようなものを追加します：$query->addExpression(':table', 'table_name', array(':table' => $table_name));

問題は、ユニオンを作成するとすぐに、テーブル名が最初のクエリの名前に置き換えられることです。

以下の例を確認してください。

$table_name = 'table_one'; 
$query_1 = db_select('table_one', 't1');
$query_1->fields('t1', array('field_1', 'field_2'));
$query_1->addExpression(':table', 'table_name', array(':table' => $table_name));

$table_name = 'table_two'; 
$query_2 = db_select('table_two', 't2');
$query_2->fields('t2', array('field_1', 'field_2'));
$query_2->addExpression(':table', 'table_name', array(':table' => $table_name));    

$table_name = 'table_three';
$query_3 = db_select('table_three', 't3');
$query_3->fields('t3', array('field_1', 'field_2'));
$query_3->addExpression(':table', 'table_name', array(':table' => $table_name));

選択を個別にチェックすると、それらはすべて正常に見え、期待される結果が得られますが、ユニオンを使用するとtable_one、いたるところにしか表示されません。

// dpq($query_1) - OK 
SELECT t1.field_1 AS field_1, t1.field_2 AS field_2, 'table_one' AS table_name
FROM 
{table_one} t1

// dpq($query_2) - OK
SELECT t2.field_1 AS field_1, t2.field_2 AS field_2, 'table_two' AS table_name
FROM 
{table_two} t2

// dpq($query_3) - OK
SELECT t3.field_1 AS field_1, t3.field_2 AS field_2, 'table_three' AS table_name
FROM 
{table_three} t3

// dpq($query_1->union($query_2)->union($query_3)) - OOPS.. 'table_one' all over the place
SELECT t1.field_1 AS field_1, t1.field_2 AS field_2, 'table_one' AS table_name
FROM 
{table_one} t1 UNION SELECT t2.field_1 AS field_1, t2.field_2 AS field_2, 'table_one' AS table_name
FROM 
{table_two} t2 UNION SELECT t3.field_1 AS field_1, t3.field_2 AS field_2, 'table_one' AS table_name
FROM 
{table_three} t3

私はこれでしばらく頭を悩ませてきたので、アイデアがあれば素晴らしいでしょう...

4

1 に答える 1

0

After a few hours of sleep I tracked it down to this function:

  // @file includes/database/select.inc
  public function arguments() {
    // ....

    // If there are any dependent queries to UNION,
    // incorporate their arguments recursively.
    foreach ($this->union as $union) {
      $args += $union['query']->arguments();
    }

    return $args;
  }

And since all the selects in the query have the same key :table then you'll end up with only one argument instead of thee.

Solution: Just make sure you use different keys for the placeholders.

So if we replace in the above example these lines (notice :table_1 & :table_2 instead of :table:

$query_2->addExpression(':table_1', 'table_name', array(':table_1' => $table_name));
$query_3->addExpression(':table_2', 'table_name', array(':table_2' => $table_name));

Voila, finally get the expected results. Hope it helps somebody, half a day lost trying to figure out why this was happening.

SELECT t1.field_1 AS field_1, t1.field_2 AS field_2, 'table_one' AS table_name
FROM 
{table_one} t1 UNION ALL SELECT t2.field_1 AS field_1, t2.field_2 AS field_2, 'table_two' AS table_name
FROM 
{table_two} t2 UNION ALL SELECT t3.field_1 AS field_1, t3.field_2 AS field_2, 'table_three' AS table_name
FROM 
{table_three} t3
于 2012-08-03T09:44:30.580 に答える