SQL NULL: Tricky Interview Question

The below is the data in sample table of name ‘DATA’. The question is how NULL performs in expressions.

The Question: What will be result when below query executed

Table: data

COL1	COL 2	COL 3
1	2	NULL

SQL Query:

SELECT 
col1 + col2, col2 + col3, col1 + col2 / col3 
FROM data;

Q) What are the three possible values returned by the sample SQL query above?

1. 3, NULL, 0
2. 3, 2, 0
3. 3, 2, 3
4. 3, NULL, NULL
5. 3, 2, NULL

The correct answer is ‘Choice 4’.

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