Create tables based on contents of other table - tsql

Question

I have a table that contains names of tables to create and the columns that that table should have:
CREATE TABLE Tables2Create (
table_name nvarchar(256)
,colum_names nvarchar(max)
)
INSERT INTO Tables2Create VALUES ('People','Name|Occupation|Hobby')
INSERT INTO Tables2Create VALUES ('Schools','Name|Place|Type ')
Now I need some TSQL that will dynamically create tables for each table in the field table_names and that will split the field column_names to decide which columns each table should have. All fields can be nvarchar's.
CREATE TABLE People (
Name nvarchar(256)
,Occupation nvarchar(256)
,Hobby nvarchar(256)
)
Any idea how to do this?

Answer 1

Below is an example using STRING_SPLIT to extract the column names and STRING_AGG to concatenate the column names and CREATE TABLE statements.
DECLARE #SQL nvarchar(MAX);
SELECT #SQL = STRING_AGG(CreateTableStatement, '')
FROM (
SELECT
'CREATE TABLE ' + QUOTENAME(table_name) + N' (' +
(
SELECT STRING_AGG(QUOTENAME(value) + ' nvarchar(256)',',')
FROM STRING_SPLIT(column_names,'|')
)
+ N');'
FROM dbo.Tables2Create
) AS CreateTableStatements(CreateTableStatement)
EXEC(#SQL);

Answer 2

Can you do this? Yes, you can. Should you? Probably not, if I am honest. Storing delimited data, as I mention in my comment, is always a design flaw; at least normalise your design.
That being said, the method I use here is an "all in one" solution; no cursors, not iteration. As you've tagged SQL Server 2019 that means we can make use of STRING_AGG. This gives something like this:
USE master;
GO
CREATE DATABASE TestDB;
GO
USE TestDB;
GO
CREATE TABLE Tables2Create (table_name sysname, --correct data type for object names
column_names nvarchar(max)
)
INSERT INTO Tables2Create VALUES (N'People',N'Name|Occupation|Hobby')
INSERT INTO Tables2Create VALUES (N'Schools',N'Name|Place|Type ');
GO
DECLARE #SQL nvarchar(MAX),
#CRLF nchar(2) = NCHAR(13) + NCHAR(10);
DECLARE #Delim nvarchar(10) = N',' + #CRLF + N' '
SET #SQL = (SELECT STRING_AGG(S.SQL,'')
FROM(SELECT #CRLF + #CRLF +
N'CREATE TABLE dbo.' + QUOTENAME(T2C.table_name) + N' (' + #CRLF + N' ' +
STRING_AGG(QUOTENAME(SS.value) + N' nvarchar(256)',#Delim) WITHIN GROUP (ORDER BY SS.[Value]) + #CRLF + N');' AS SQL
FROM dbo.Tables2Create T2C
CROSS APPLY STRING_SPLIT(T2C.column_names,N'|') SS
GROUP BY T2C.table_name) S);
PRINT #SQL; --Your best friend
EXEC sys.sp_executesql #SQL;
GO
USE master;
GO
DROP DATABASE TestDB;
db<>fiddle