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The query will generate the following output from which we can see that it has returned NULL as the name for names which do not have a middle name. SELECT first_name +' ' + middle_name + ' ' + last_name 'Customer Name' We can try to concatenate the different name fields using the following query. To understand the scenario let us consider the below sample customer table containing customer names and contact numbers. The COALESCE function comes to the rescue here by ensuring that the concatenation does not break. Concatenating the different parts of the name for such names produces NULL as the result because the concatenation process breaks at missing or NULL values. However, it does not work if some columns (like middle name, husbands last name etc.) do not contain any value or contains NULL value. The same is usually achieved through string concatenation. But when presenting the information for display and viewing it has to be presented as a single unit i.e. The most ubiquitous example is that of a person’s name which consists of multiple parts (in multiple columns) all of which do not exist for all names. Sometimes a single piece of information is spread across multiple columns in a table. 1) SQL Server COALESCE – string concatenation example We will understand the above-mentioned use cases through the following examples. expression – a literal (numeric or string) value or anything (including table column, parameter, variable, subqueries, mathematical operation, function etc.) that returns a single numeric or string value.COALESCE() – function name which takes multiple expressions as arguments looking for and returning the first non-null value.
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The basic syntax of SQL Server COALESCE statement is given below. There are quite a few practical use cases of the COALESCE function of which the most common are string concatenation, pivoting and column value validation and consolidation.
Coalesce sql server how to#
The objective of this SQL Server tutorial is to teach you how to use the COALESCE function to find the first non-null value in a list containing both NULL and valid values.