Terraform 无法为rds子网组提供计数和子网ID

我无法在aws\u db\u subnet\u组中提供多个子网ID

resource "aws_subnet" "rds_subnet_" {

  count             = 3
  vpc_id            = aws_vpc.app_vpc.id
  cidr_block        = cidrsubnet(aws_vpc.app_vpc.cidr_block, 8, count.index+30)
  availability_zone = data.aws_availability_zones.available.names[count.index]
  
  tags = {
    Name = "rds_subnet_${count.index}"
  }
  
  depends_on = [aws_vpc_dhcp_options_association.dns_resolver]
}


#make rds subnet group
  resource "aws_db_subnet_group" "rdssubnet" {
  name       = "database subnet"
  #subnet_ids  = [aws_subnet.rds_subnet_[0].id, aws_subnet.rds_subnet_[1].id, aws_subnet.rds_subnet_[2].id]
  subnet_ids = ["${aws_subnet.rds_subnet_.*.id}"]
}


#provision the database
resource "aws_db_instance" "database" {
  identifier             = "database"
  instance_class         = var.db_instance_type
  allocated_storage      = var.db_size
  engine                 = "mysql"
  multi_az               =  true
  apply_immediately      =  false
  name                   = "dev_database"
  password               = var.rds_password
  username               = var.rds_user
  engine_version         = "5.7.21"
  skip_final_snapshot    = true
  db_subnet_group_name   = aws_db_subnet_group.rdssubnet.name
  vpc_security_group_ids = [aws_security_group.rds_security_group.id]
}

错误：在rds.tf第5行的资源“aws\u db\u subnet\u group”“rdssubnet”中： 5:subnet_id=[“${aws_subnet.rds_subnet.*.id}] |---------------- |aws_subnet.rds_subnet是一个包含3个元素的元组

属性“子网ID”的值不正确：元素0：需要字符串。

是子网ID的列表

因此，不是：

subnet_ids = ["${aws_subnet.rds_subnet_.*.id}"]

请使用：

subnet_ids = aws_subnet.rds_subnet_.*.id