---
title: "SQL NULL: Tricky Interview Question"
description: "SQL NULL example query and how it returns when you write query. Read more."
url: https://srinimf.com/2015/11/11/sql-query-to-describe-null-value-best-example/
date: 2015-11-11
modified: 2026-10-10
author: "Srini"
image: https://i0.wp.com/srinimf.com/wp-content/uploads/2015/11/image.png?fit=1024%2C768&ssl=1
categories: ["SQL"]
tags: ["SQL NULL query", "SQL tips and tricks"]
type: post
lang: en
---

# SQL NULL: Tricky Interview Question

Below is the data in the sample table named ‘DATA’. The question is how NULL performs in expressions.

Related[Named Vs. Unnamed PL/SQL Procedures](https://srinimf.com/2022/01/15/named-vs-unnamed-pl-sql-procedures/)

## The Question: What will be the result when the below query executed

**Table***: data*

Related[DISTINCT Vs. COLLECT_SET: Top Differences](https://srinimf.com/2024/09/22/distinct-vs-collect_set-top-differences/)

| **COL1** | **COL 2** | **COL 3** |
| --- | --- | --- |
| 1 | 2 | NULL |

*Data present in the Table*

**[SQL Query](https://srinimf.com/2024/06/18/sql-query-to-find-null-and-non-null-percentage-of-column/):**

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

Q) What are the three possible values returned by the [sample SQL query](https://srinimf.com/2014/10/14/db2-identity-column/) 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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