COALESCE Statement in SQL Server: Tips and Examples

COALESCE Statement in SQL Server is easier to understand when the core ideas are paired with practical examples. The sections below explain the topic clearly, highlight useful steps, and point out details that can prevent common errors.

This guide will show you in detail how to use the COALESCE statement handling function in SQL Server with specific syntax and examples to better visualize and capture functions.

Describe

The COALESCE statement returns the expression with the first non-NULL value among the passed expressions. If all expressions are NULL then COALESCE will return NULL.

Syntax

To use the COALESCE statement in SQL Server, we use the following syntax:

 COALESCE (bieuthuc_1, bieuthuc_2,. bieuthuc_n)

Parameters :

bieuthuc_1, bieuthuc_2,. bieuthuc_n : is an expression of any type. All of these expressions must be in the same form or convert to the same form. As an example,, bieuthuc_1 is a string type, bieuthuc_2 to bieuthuc_n must also be a string type, similar to bieuthuc_1 is a numeric type then bieuthuc_2 to bieuthuc_n must also be numeric type.

Note :

COALESCE can be used in later versions of SQL Server: SQL Server 2017, SQL Server 2016, SQL Server 2014, SQL Server 2012, SQL Server 2008 R2, SQL Server 2008, and SQL Server 2005.

As an example,

Take a look and explore some examples of COALESCE statements in SQL Server.

 SELECT COALESCE(NULL, NULL, 'TipsMake.com', NULL, 'ChuyenCongNghe'); 
 Result: 'TipsMake.com' 
 
 SELECT COALESCE(NULL, 'TipsMake.com', 'Tipsmake'); 
 Result: 'TipsMake.com' 
 
 SELECT COALESCE(NULL, NULL, 1, 2, 3, NULL, 4); 
 Result: 1

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FAQ

What should you know about describe?

The COALESCE statement returns the expression with the first non-NULL value among the passed expressions. If all expressions are NULL then COALESCE will return NULL.