Here is the code snippets for MS SQL deployment using YML code in AWS. If you wish to make it AD integrated then review the details given in comment section.

AWSTemplateFormatVersion: '2010-09-09'
Description: Creates an empty SQL Server RDS database as an example for automated deployments.
Parameters:
  SqlServerInstanceName:
    NoEcho: 'false'
    Description: RDS SQL Server Instance Name
    Type: String
    Default: MyAppInstance
    MinLength: '1'
    MaxLength: '63'
    AllowedPattern: "[a-zA-Z][a-zA-Z0-9]*"
  DatabaseUsername:
    AllowedPattern: "[a-zA-Z0-9]+"
    ConstraintDescription: DBAdmin
    Description: Database Admin Account User Name
    MaxLength: '16'
    MinLength: '1'
    Type: String
    Default: 'DBAdmin'
  DatabasePassword:
    AllowedPattern: "^(?=.*[0-9])(?=.*[a-zA-Z])([a-zA-Z0-9]+)"
    ConstraintDescription: Must contain only alphanumeric characters with at least one capital letter and one number.
    Description: The database admin account password.
    MaxLength: '41'
    MinLength: '6'
    NoEcho: 'true'
    Type: String
    Default: Admin123
  DBEngine:
    Description: Select Database Engine
    Type: String
    AllowedValues: [Express, Enterprise]
  #Following paramter can be placed if SQL needs to be AD integrated.
  #DomainID:
  # Description: Enter the Domain ID
  # Type: String

Mappings:
 SQLTOEngineType:
  Express:
   Engine: sqlserver-ex
  Enterprise:
   Engine: sqlserver-ee

Resources:
  SQLDatabase:
    Type: AWS::RDS::DBInstance
    Properties:
      DBInstanceIdentifier:
        Ref: SqlServerInstanceName
      LicenseModel: license-included
      Engine: !FindInMap [SQLTOEngineType, !Ref 'DBEngine', Engine]
      EngineVersion: 13.00.4466.4.v1
      DBInstanceClass: db.t2.micro
      AllocatedStorage: '20'
      MasterUsername:
        Ref: DatabaseUsername
      MasterUserPassword:
        Ref: DatabasePassword
      PubliclyAccessible: 'true'
      BackupRetentionPeriod: '1'
      #If SQL RDS needs to Active Directory Integrated then uncomment following parameter.
      #Domain: !ImportValue Directory-ID
      #OR
      #!Ref DomainID
      #IAM role is mandate for AD integration
      #DomainIAMRoleName: 'rds-directoryservice-access-role'
Outputs:
   SQLDatabaseEndpoint:
     Description: Database endpoint
     Value: !Sub "${SQLDatabase.Endpoint.Address}:${SQLDatabase.Endpoint.Port}"

1. Save above code in SQLRDS.YML file.
2. Open AWS management console, In Cloud formation section, select New Template, select Upload a template to Amazon S3. Select SQLRDS.YML file then follow the wizard with all default options.
3. Once deployment successfully completes, you would see events like below screenshot.

#domain, #domainiamrolename, #domainid, #following, #iam, #if, #or