Dynamic view with sysobjects tables - sql

Question

I want to alter a view using a T-SQL script dynamic. Each month I have a new table in my database, I want to include the new table in my view. My idea is to create a var inside a T-SQL procedure and then build the sql statment to create the code I will use to alter the view. With this I only need to EXEC (#SqlView). The challenge now is to get (#SqlResults) in a string. Any ideas?
SQL for the view (#SqlView)
select a, b from table01
union all
select a, b from table02
union all
select a, b from table03
SQL statement for the view code (#SqlResults)
select 'select a,b from '+so.name' union all' from sysobjects so
join sys.schemas s
On so.uid = s.schema_id
where so.xtype = 'U'
and so.name like '%table0%'

Answer 1

Here is another approach that doesn't use a loop.
declare #SqlResults nvarchar(max) = ''
select #SqlResults = #SqlResults + 'select a,b from ' + t.name + ' union all '
from sys.tables t
where t.name like '%table0%'
select #SqlResults = 'ALTER VIEW SomeView as ' + left(#SqlResults, LEN(#SqlResults) - 10)
select #SqlResults
--Uncomment the exec line when you are comfortable
--exec sp_executesql #SqlResults

Answer 2

This is the SQL that I use when trying to generate a script for every table, altered to plug in your specific details:
DECLARE #SQLTable TABLE
(
ID INT IDENTITY(1,1) NOT NULL,
Sequel VARCHAR(4000) NOT NULL
)
INSERT INTO #SQLTable (Sequel)
SELECT
'SELECT A, B FROM ' + TABLE_NAME + ' UNION ALL'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '%table0%'
DECLARE #Looper INT = (SELECT MAX(ID) FROM #SQLTable)
DECLARE #Counter INT = 0
DECLARE #ExecSQL VARCHAR(MAX) =
--'' -- use this if you just want to run the SQL
'ALTER VIEW MyView AS
' -- use this if you want to alter a view
WHILE #Counter <= #Looper
BEGIN
SET #Counter = #Counter + 1
SELECT #ExecSQL = #ExecSQL + '
' + Sequel
FROM #SQLTable
WHERE ID = #Counter
END
SET #ExecSQL =
LEFT (#ExecSQL, LEN(#ExecSQL) - 10) -- the LEFT() function is to remove the final UNION ALL
+ '
GO'
PRINT (#ExecSQL)

Answer 3

There is probably a way to do this with cursors, but I'm not too familiar with that syntax. What I've done in similar situations is used a few variables and either a table variable or a temp table. I also don't have much opportunity to work with dynamic sql very much, so this is a bit of a shot in the dark.
declare #view_script as varchar(4000) = 'alter view dbo.my_view as select a, b from table01'
declare #cur_table as integer = 2
declare #table_list as table (table_num integer identity(1,1), table_nm varchar(100))
insert into #table_list (table_nm)
select name
from sys.tables
where name like '%table0%'
while #cur_table <= (select max(table_num) from #table_list)
begin
select #view_script = #view_script + 'union all ' + char(10) + select a, b from ' + table_nm
from #table_list
where #table_list.table_num = #cur_table
#cur_table = #cur_table + 1
end
exec #view_script
Let me know if this works or if there was something you had to change to make it work.