COL_NAME function in SQL Server

COL_NAME is a predefined SQL server function that returns the name of a table column using table and column identification numbers.

COL_NAME (table_id, column_id)

COL_NAME function takes two parameters which is table and column identification numbers like specified in the above statement.

Let's look into an example of AdventureWorks2019 database,

SELECT TOP (1000) [BusinessEntityID]
      ,[PersonType]
      ,[NameStyle]
      ,[Title]
      ,[FirstName]
      ,[MiddleName]
      ,[LastName]
      ,[Suffix]
      ,[EmailPromotion]
      ,[AdditionalContactInfo]
      ,[Demographics]
      ,[rowguid]
      ,[ModifiedDate]
  FROM [AdventureWorks2019].[Person].[Person]

Here is the above statement result set,

Let's see how to retrieve the column name FirstName using the COL_NAME function,

SELECT COL_NAME(OBJECT_ID('Person.Person'), 5) AS ColumnName; /* COL_NAME (table_id, column_id) */

The OBJECT_ID function returns the identification number of a specified table and number 5 represents the column number.

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