多个 UNION 查询不起作用

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）？ 该怎么办？

Answer 1

您已将问题标记为 MySQL，并且使用方括号[] 。 据我所知，方括号不适用于MySQL和仅适用于Microsoft产品（SQL服务器/ MS接入）。 因此，如果您需要包含表/列名称，请使用反引号` 。

从文档：

标识符引号字符是反引号（“`”）：

所以我认为你的查询应该是：

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

这是一个 MyODBC 错误，请参阅此处的官方条目。 直到今天，它仍然开放......

[编辑] 我找到了一个简单的解决方案：myODBC 只会理解带有 ONE UNION （或UNION ALL ）的查询。 所以你必须用()包裹UNION的正确部分。 另外，您需要以;结束每个查询; ， 像这样：

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，您也必须对这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前面添加 ''&，如下所示：SELECT ''&COUNT(*) AS MYNR,...

通过这种方式，我设法使用了 UNION ALL 4x。

希望它可以帮助某人

错误链接