When joining two tables using Full Outer Join, I am receiving results with NULL values in every column. The row count is the same as the count of the larger table. I would expect that at least one table columns would have values. Here is my simple select statement:
SELECT * FROM InputXML X
FULL OUTER JOIN ACM ON X.[file_name] = ACM.AllCharts
这是一个完全连接,它将在左侧或右侧返回null,但是如果返回的行中包含null,则必须检查是否具有X. [file_name]或ACM.AllCharts带有Null值,因为当您比较null时= null不会给您任何结果,因为null不是一个值,它在数学上有点未知或无限。
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