How can you combine multiple columns into one in SQL Server?

 In SQL Server, you can combine multiple columns into one using the CONCAT() function or the + operator. Here are two ways to do it:

1. Using CONCAT() function:

The CONCAT() function joins two or more strings together and automatically handles NULL values by treating them as empty strings.

SELECT CONCAT(Column1, Column2, Column3) AS CombinedColumn
FROM YourTable;

2. Using the + operator:

You can also use the + operator to concatenate columns, but be aware that if any of the columns contain NULL values, the result will be NULL.

SELECT Column1 + Column2 + Column3 AS CombinedColumn
FROM YourTable;

If you want to handle NULL values explicitly (for example, by replacing them with an empty string), you can use the ISNULL() or COALESCE() function:

SELECT ISNULL(Column1, '') + ISNULL(Column2, '') + ISNULL(Column3, '') AS CombinedColumn
FROM YourTable;

Or using COALESCE():

SELECT COALESCE(Column1, '') + COALESCE(Column2, '') + COALESCE(Column3, '') AS CombinedColumn
FROM YourTable;

This will ensure that any NULL values are treated as empty strings during concatenation.