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

Data present in the Table

SQL Query:

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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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.