SQL Puzzle | Check input parameter value is integer or not

This question was asked to me in one of the technical interviews I had recently attended. Here we have to accept an input string and check whether it is an integer value or not. I told him about the Try_Convert but he told me to come up the custom logic. Please check out the sample input values and sample expected output below.

Sample Input

DECLARE @ AS VARCHAR(100) = ‘2147483648.1’
DECLARE @ AS VARCHAR(100) = ‘F’
DECLARE @ AS VARCHAR(100) = ‘9F’
DECLARE @ AS VARCHAR(100) = ‘\$’
DECLARE @ AS VARCHAR(100) = ’20’

Expected Output

Not an Integer
Not an Integer
Not an Integer
Not an Integer
An Integer

Rules/Restrictions

The solution should be should use “SELECT” statement or “CTE”.
Add your solution(s) in the comments section or send you solution(s) to pawankkmr@gmail.com

SOLUTION 1 | Using Try_Convert

 ``` -- DECLARE @ AS VARCHAR(100) = '2147483648.1' IF TRY_PARSE(@ AS INT) IS NULL PRINT 'Not an Integer' ELSE PRINT 'An Integer' GO DECLARE @ AS VARCHAR(100) = 'F' IF TRY_PARSE(@ AS INT) IS NULL PRINT 'Not an Integer' ELSE PRINT 'An Integer' GO DECLARE @ AS VARCHAR(100) = '9F' IF TRY_PARSE(@ AS INT) IS NULL PRINT 'Not an Integer' ELSE PRINT 'An Integer' GO DECLARE @ AS VARCHAR(100) = '\$' IF TRY_PARSE(@ AS INT) IS NULL PRINT 'Not an Integer' ELSE PRINT 'An Integer' GO DECLARE @ AS VARCHAR(100) = '20' IF TRY_PARSE(@ AS INT) IS NULL PRINT 'Not an Integer' ELSE PRINT 'An Integer' GO -- ```

SOLUTION 2 | Using Numbers Table

 ``` -- DECLARE @ AS VARCHAR(100) = '2147483648.1' SELECT CASE WHEN SUM(CASE WHEN ASCII(n) BETWEEN 48 AND 57 THEN 1 END) = SUM(1) THEN 'An Integer' ELSE 'Not an Integer' END IsInteger FROM ( SELECT DISTINCT SUBSTRING(@,Number,1) n FROM Master..Spt_Values WHERE Number > 0 AND Number <= DATALENGTH(@) )r GO DECLARE @ AS VARCHAR(100) = 'F' SELECT CASE WHEN SUM(CASE WHEN ASCII(n) BETWEEN 48 AND 57 THEN 1 END) = SUM(1) THEN 'An Integer' ELSE 'Not an Integer' END IsInteger FROM ( SELECT DISTINCT SUBSTRING(@,Number,1) n FROM Master..Spt_Values WHERE Number > 0 AND Number <= DATALENGTH(@) )r GO DECLARE @ AS VARCHAR(100) = '9F' SELECT CASE WHEN SUM(CASE WHEN ASCII(n) BETWEEN 48 AND 57 THEN 1 END) = SUM(1) THEN 'An Integer' ELSE 'Not an Integer' END IsInteger FROM ( SELECT DISTINCT SUBSTRING(@,Number,1) n FROM Master..Spt_Values WHERE Number > 0 AND Number <= DATALENGTH(@) )r GO DECLARE @ AS VARCHAR(100) = '\$' SELECT CASE WHEN SUM(CASE WHEN ASCII(n) BETWEEN 48 AND 57 THEN 1 END) = SUM(1) THEN 'An Integer' ELSE 'Not an Integer' END IsInteger FROM ( SELECT DISTINCT SUBSTRING(@,Number,1) n FROM Master..Spt_Values WHERE Number > 0 AND Number <= DATALENGTH(@) )r GO DECLARE @ AS VARCHAR(100) = '20' SELECT CASE WHEN SUM(CASE WHEN ASCII(n) BETWEEN 48 AND 57 THEN 1 END) = SUM(1) THEN 'An Integer' ELSE 'Not an Integer' END IsInteger FROM ( SELECT DISTINCT SUBSTRING(@,Number,1) n FROM Master..Spt_Values WHERE Number > 0 AND Number <= DATALENGTH(@) )r GO -- ```

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

Enjoy !!! Keep Learning

Pawan Khowal

Http://MSBISkills.com

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