Query in an empty table

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What is the return of a query in an empty table?

Example, I am running this SQL Command: 

select Value
  from AVL_AnalogInput1
 where TimeStamp = (select max(TimeStamp) from AVL_AnalogInput1) .

Table AVL_AnalogInput1.

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Outcome of the consultation.

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My question is, what kind of result are you returning to me? Are you returning me null? Or are you simply not returning anything to me? I can use this result to check if the table is empty?

sql-server

  • I think this one link can help you

  • Note that your table is not empty, it contains a row with NULL values. NULL has a very specific behavior, especially in comparisons.

1 answer

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See @@rowcount to see if you returned any lines in SELECT execution. 

-- código #1
SELECT Value
  from AVL_AnalogInput1
  where TimeStamp = (select max(TimeStamp) from AVL_AnalogInput1);

IF @@rowcount = 0
  PRINT 'nada a declarar';

Details in @@rowcount.

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