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SQL PUZZLE | Output of SELECT COUNT(NULL) / SELECT COUNT(0) / SELECT COUNT($) ?? | SQL INTERVIEW QUESTION

In this puzzle you have to provide the output of below statements and back them with the reasons. For more details please refer statements below-

–Q1. What will be the output of SELECT COUNT(NULL)

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SELECT COUNT(NULL)

--

OUTPUT

Msg 8117, Level 16, State 1, Line 2
Operand data type NULL is invalid for count operator.

Error clearly says that you cannot use NULL in Count function.

–Q2. What will be the output of SELECT COUNT(0)

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SELECT COUNT(0)

--

OUTPUT

The output will be 1 here.

–Q3. What will be the output of SELECT COUNT($)

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SELECT COUNT($)

--

OUTPUT

The output will be 1 here. Apart from NULL you will always get 1

Add your solution(s) in the comments section or send you solution(s) to pawankkmr@gmail.com

Add a comment if you have any solution in mind. I would love to learn it. We all need to learn.

Pawan Khowal

Pawan is a SQL Server Developer. If you need any help in writing code/puzzle or training please email at – pawankkmr”AT”gmail.com. Meanwhile please go throgh the top pages from his blog.

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