UpdateItem Dynamodb Boto3 Says Wrong Query

Question

I am trying to increment values of specific columns. I am using Boto3.

update_query = '#clicks.#OS.#os = #clicks.#OS.#os + :inc, #clicks.#Brands.#brand = #clicks.#Brands.#brand + :inc, #clicks.#RAMs.#ram = #clicks.#RAMs.#ram + :inc'
table_urls.update_item(
            Key={
                'urlid': urlid
            },
            UpdateExpression=update_query,
            ExpressionAttributeValues={
                ':inc' : Decimal(1)
            },
            ExpressionAttributeNames={
                "#os"   : os,
                "#brand": brand,
                "#ram"  : ram,
                "#clicks": "clicks",
                "#OS"   : "OS",
                "#Brands": "Brands",
                "#RAMs"  : "RAMs"
            },
            ReturnValues='NONE'
        )

Here is Error StackTrace: Error:

An error occurred (ValidationException) when calling the UpdateItem operation: Invalid UpdateExpression: Syntax error; token: "#clicks", near: "#clicks."
QUERY::>> #clicks.#OS.#os = #clicks.#OS.#os + :inc, #clicks.#Brands.#brand = #clicks.#Brands.#brand + :inc, #clicks.#RAMs.#ram = #clicks.#RAMs.#ram + :inc

Answer 1

Try adding SET at the start of the update_query string. Everything rest seems proper.

update_query = 'SET #clicks.#OS.#os = #clicks.#OS.#os + :inc, #clicks.#Brands.#brand = #clicks.#Brands.#brand + :inc, #clicks.#RAMs.#ram = #clicks.#RAMs.#ram + :inc'
table_urls.update_item(
            Key={
                'urlid': urlid
            },
            UpdateExpression=update_query,
            ExpressionAttributeValues={
                ':inc' : Decimal(1)
            },
            ExpressionAttributeNames={
                "#os"   : os,
                "#brand": brand,
                "#ram"  : ram,
                "#clicks": "clicks",
                "#OS"   : "OS",
                "#Brands": "Brands",
                "#RAMs"  : "RAMs"
            },
            ReturnValues='NONE'
        )