Create table variable with exact same structure of another table - sql-server

Question

In T-SQL, I can create a table variable using syntax like
DECLARE #table AS TABLE (id INT, col VARCHAR(20))
For now, if I want to create an exact copy of a real table in the database, I do something like this
SELECT *
FROM INFOMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'MY_TABLE_NAME'
to check the column datatype and also max length, and start to create the #table variable, naming the variable, datatype and max_length one by one which is not very effective. May I know if there is any simpler way to do it like
DECLARE #table AS TABLE = SOME_REAL_TABLE_IN_DATABASE
Furthermore, is there any way to retrieve the column name, data type and max length of the column and use it directly in the declaration like
DECLARE #table AS TABLE (#col1_specs)
Thank you in advance.
EDIT:
Thanks for the answers and comments, we can do that for #table_variable but only in dynamic SQL and it is not good for maintainability. However, we can do that using #temp_table.
Based on the answer by Ezlo, we can do something like this :
SELECT TABLE.* INTO #TEMP_TABLE FROM TABLE
For more information, please refer to this answer.
Difference between temp table and table variable (stackoverflow)
Difference between temp table and table variable (dba.stackexchange)

Answer 1

Object names and data types (tables, columns, etc.) can't be parameterized (can't come from variables). This means you can't do the following (which would be required to copy a table structure, for example):
DECLARE #TableName VARCHAR(50) = 'Employees'
SELECT
T.*
FROM
#TableName AS T
The only workaround is to use dynamic SQL:
DECLARE #TableName VARCHAR(50) = 'Employees'
DECLARE #DynamicSQL VARCHAR(MAX) = '
SELECT
T.*
FROM
' + QUOTENAME(#TableName) + ' AS T '
EXEC (#DynamicSQL)
However, variables (scalar and table variables) declared outside the dynamic SQL won't be accessible inside as they lose scope:
DECLARE #VariableOutside INT = 10
DECLARE #DynamicSQL VARCHAR(MAX) = 'SELECT #VariableOutside AS ValueOfVariable'
EXEC (#DynamicSQL)
Msg 137, Level 15, State 2, Line 1
Must declare the scalar variable "#VariableOutside".
This means that you will have to declare your variable inside the dynamic SQL:
DECLARE #DynamicSQL VARCHAR(MAX) = 'DECLARE #VariableOutside INT = 10
SELECT #VariableOutside AS ValueOfVariable'
EXEC (#DynamicSQL)
Result:
ValueOfVariable
10
Which brings me to my conclusion: if you want to dynamically create a copy of an existing table as a table variable, all the access of your table variable will have to be inside a dynamic SQL script, which is a huge pain and has some cons (harder to maintain and read, more prone to error, etc.).
A common approach is to work with temporary tables instead. Doing a SELECT * INTO to create them will inherit the table's data types. You can add an always false WHERE condition (like WHERE 1 = 0) if you don't want the actual rows to be inserted.
IF OBJECT_ID('tempdb..#Copy') IS NOT NULL
DROP TABLE #Copy
SELECT
T.*
INTO
#Copy
FROM
YourTable AS T
WHERE
1 = 0

Answer 2

The answer for both questions is simple NO.
Although, I agree with you that T-SQL should change in this way.
In the first case, it means having a command to clone a table structure.
Of course, there is a possibility to make your own T-SQL extension by using SQLCLR.