Question

多个UNION查询：

SELECT [Ordine numero] AS ordine, [data ordine] AS data, comm AS commessa
FROM [archivio globale]
WHERE [ordine numero] IS NOT NULL

UNION

SELECT [numero ordine cliente] AS ordine, [data ordine cliente] AS data, numero AS commessa
FROM [ricambi]
WHERE [numero ordine cliente] IS NOT NULL

UNION

SELECT [numero ordine cliente] AS  ordine, [data ordine cliente] AS data, numero AS commessa
FROM [trasferte]
WHERE [numero ordine cliente] IS NOT NULL

ORDER BY [ordine];

它不起作用：我收到错误消息：

[mysql][odbc 5.1 Driver][mysqld-5.5.14]You have an error in your SQL syntax ...

虽然单个UNION查询正常工作（没有第二个UNION语句）？怎么办？

Answer 1

您已将问题标记为MySQL，并使用方括号[]。据我所知，方括号不对MySQL有效，仅对Microsoft产品有效（SQL Server / MS Access）。因此，如果您需要附加表/列名称，请使用反引号`。

From the documentation:

标识符引号字符是反引号（“`”）：

所以我认为您的查询应该是：

SELECT `Ordine numero` AS ordine, `data ordine` AS data, comm AS commessa
FROM `archivio globale`
WHERE `ordine numero` IS NOT NULL

UNION ALL

SELECT `numero ordine cliente` AS ordine, `data ordine cliente` AS data, numero AS commessa
FROM `ricambi`
WHERE `numero ordine cliente` IS NOT NULL

UNION ALL

SELECT `numero ordine cliente` AS  ordine, `data ordine cliente` AS data, numero AS commessa
FROM `trasferte`
WHERE `numero ordine cliente` IS NOT NULL

ORDER BY `ordine`;

编辑，如果您使用的是MS Access，则需要使用方括号：

SELECT *
FROM
(
  SELECT [Ordine numero] AS ordine, [data ordine] AS data, comm AS commessa
  FROM [archivio globale]
  WHERE [ordine numero] IS NOT NULL

  UNION ALL

  SELECT [numero ordine cliente] AS ordine, [data ordine cliente] AS data, numero AS commessa
  FROM [ricambi]
  WHERE [numero ordine cliente] IS NOT NULL

  UNION ALL

  SELECT [numero ordine cliente] AS  ordine, [data ordine cliente] AS data, numero AS commessa
  FROM [trasferte]
  WHERE [numero ordine cliente] IS NOT NULL
) x
ORDER BY [ordine];

Answer 2

这是MyODBC的错误，请参阅offical entry here。截至今天，它仍然开放......

[编辑]我找到了一个简单的解决方案：myODBC只能理解一个UNION（或UNION ALL）的查询。所以你必须用UNION包裹()的右边部分。另外，您需要使用;结束每个查询，如下所示：

SELECT [Ordine numero] AS ordine, [data ordine] AS data, comm AS commessa
FROM [archivio globale]
WHERE [ordine numero] IS NOT NULL;

UNION ALL (

SELECT [numero ordine cliente] AS ordine, [data ordine cliente] AS data, numero AS commessa
FROM [ricambi]
WHERE [numero ordine cliente] IS NOT NULL;

UNION ALL

SELECT [numero ordine cliente] AS  ordine, [data ordine cliente] AS data, numero AS commessa
FROM [trasferte]
WHERE [numero ordine cliente] IS NOT NULL
);

当然，您也必须对此部分应用相同的方法。例如，如果您在查询中还需要一个UNION ALL：

SELECT [Ordine numero] AS ordine, [data ordine] AS data, comm AS commessa
FROM [archivio globale]
WHERE [ordine numero] IS NOT NULL;

UNION ALL (

SELECT [numero ordine cliente] AS ordine, [data ordine cliente] AS data, numero AS commessa
FROM [ricambi]
WHERE [numero ordine cliente] IS NOT NULL;

UNION ALL (

SELECT [numero ordine cliente] AS  ordine, [data ordine cliente] AS data, numero AS commessa
FROM [trasferte]
WHERE [numero ordine cliente] IS NOT NULL;

UNION ALL

SELECT [numero ordine cliente] AS  ordine, [data ordine cliente] AS data, numero AS commessa
FROM [xxx]
WHERE [numero ordine cliente] IS NOT NULL
));

Answer 3

在我的情况下，MySQL链接到MDB的表也给了我同样的错误。经过多个小时的搜索和尝试，我的解决方案是在第一列的前面添加“＆”，如下所示：选择''＆COUNT（*）作为MYNR，...

这样，我设法使用了UNION ALL 4x。

希望它对某人有帮助

The link to the bug

多个UNION查询不起作用

3 个答案: