How to check if Columns exits in SQL Server table?

To check if columns exist in the SQL server table, I will AdventureDatabase as sample DB and table employee, and I will check if 'FullName' exists 

IF COL_LENGTH('Employee','FullName') IS NULL
BEGIN
   PRINT N'Column does not exists.';  
END

Output:

Column does not exists.

Now, I will if column 'Gender', which exists in real, so I have updated query to add "Is Not NULL"

IF COL_LENGTH('Employee','Gender') IS NOT NULL
BEGIN
   PRINT N'Column exists.';  
END

Output:

Column exists.

That's it.

Another approach

In this approach, we will add a column if it doesn't exist in the table using INFORMATION_SCHEMA.COLUMNS

IF NOT EXISTS(
  SELECT *
  FROM INFORMATION_SCHEMA.COLUMNS
  WHERE 
    [TABLE_NAME] = 'Employee'
    AND [COLUMN_NAME] = 'FullName')
BEGIN
  ALTER TABLE [Employee]
    ADD [FullName] Varchar(100) NULL
END

The above query will add a new column "FullName" in the table, if it doesn't exists, since it wasn't available, after running the above query new columns is added.

Here is the simple query to check if column exists in SQL Server

IF COL_LENGTH('schemaName.tableName', 'columnName') IS NOT NULL
BEGIN
    -- Column Exists
END

OR

if you want to drop column if it exists (SQL Server 2016 or above)

ALTER TABLE TableName DROP COLUMN IF EXISTS ColumnName

Thanks.