関連ワード:  sql server if is null or empty    sql server check is null or empty    sql server if string is null or empty    sql server check if string is null or empty    sql server check if variable is null or empty    sql server check if parameter is null or empty    sql server check if column is null or empty    sql server check if value is null or empty    sql server check if datetime is null or empty    sql server check if field is null or empty