sql - How to keep LongText field value from getting trimmed?

Question

I have an MS-Access database with two tables, both containing a LongText field, Description. I want to union these tables and get the result in one dataset. The problem is that uinon trims the field values to 255 characters.

This is my query:

SELECT Description, LenBefore, Len(Description) AS LenAfter FROM (
  SELECT Description, Len(Description) AS LenBefore FROM References
UNION
  SELECT Description, Len(Description) AS LenBefore FROM KeyWords
)

The result:

The MDB file is in 2002-2003 file format, and I'm running this in MS-Access 2016 64x.

Is there any way that I can get the full text in one single query?

Answer 1

进入查询 SQL 视图并将 UNION 更改为 UNION ALL。

在 UNION 中，必须对结果进行重复数据删除，这意味着进行比较。Access 只允许比较最多 255 个字符，因此会修剪该字段。UNION ALL 不需要重复数据删除，因此不会发生这种行为。