Question: I wish to write an SQL statement for SQL Server that Selects entry's from a column witch contains a value sum of power of 2 (2^n), 
for instance I have TABLE xxx:

```sql
_________________________________________________________
| id | col_pow |col_pow=sum of element power of 2 (2^n) |
|----|---------|----------------------------------------|
| 1  | 11      |11  = 8+2+1   = 2^3 + 2^1 +2^0          |           
| 2  | 3       |3   = 2+1     = 2^1 + 2^0               |
| 3  | 514     |514 = 512+2   = 2^9 + 2^1               |
| 4  | 49      |49  = 32+16+1 = 2^5 + 2^4 +2^0          |
| 5  | 7       |7   = 4+2+1   = 2^2 + 2^1 +2^0          |
---------------------------------------------------------

```

EX. SELECT

1) `SELECT id TABLE xxx WHERE col_pow can_contains 4 (=2^2)`

* expected result:

```sql
| id |
|----|
| 5  |

```

2) `SELECT id TABLE xxx WHERE col_pow can_contains 2 (=2^1)`

* expected result:

```sql
| id |
|----|
| 1  |
| 2  |
| 3  |
| 4  |
| 5  |

```

3) `SELECT id TABLE xxx WHERE col_pow can_contains 512(=2^9)`

* expected result:

```sql
| id |
|----|
| 3  |

```

How to write the 3 statements?

Answer: 
I use `aws iam get-account-authorization-details` to view the current IAM roles in my AWS China accounts, which are created using AWS console.

Then I found lines containing `"Service": "ec2.amazonaws.com.cn"`.

So using `ec2.amazonaws.com.cn` to replace `ec2.amazonaws.com` works without any problem.

I mean the content of `main.tf` should be

```
provider "aws" {
  access_key = var.access_key
  secret_key = var.secret_key
  region  = var.region
}

resource "aws_iam_role" "role" {
  name               = "TestRole"
  assume_role_policy = data.aws_iam_policy_document.policy_doc.json
}

data "aws_iam_policy_document" "policy_doc" {
  statement {
    actions = ["sts:AssumeRole"]

    principals {
      type        = "Service"
      identifiers = ["ec2.amazonaws.com.cn"]
    }
  }
}

```
China is different as you said.

`ec2.amazonaws.com` will not work in China, instead you have to use something along the lines of `ec2.cn-northwest-1.amazonaws.com.cn` 

Here you have the list of all endpoints <https://docs.amazonaws.cn/en_us/aws/latest/userguide/endpoints-Ningxia.html>

Also a recommended read about IAM in China: <https://docs.amazonaws.cn/en_us/aws/latest/userguide/iam.html#general-info>