T-SQL query each database in instance without using a cursor - sql-server

Question

Using SQL Server 2012.
Using the system views stored for each database I wanted to keep a summary of index behavior for all indexes across the instance. The code below collects some stats and drops them in a table for later use. The snag is, I had to use a cursor to loop through the databases in the instance. Can anyone suggest a nicer way of doing this without having to use the cursor?
USE Master
GO
-- If the procedure already exists then update it.
IF OBJECT_ID('sp_index_stats') IS NOT NULL
DROP PROCEDURE sp_index_stats
GO
CREATE PROCEDURE sp_index_stats AS
DECLARE #dbname NVARCHAR(128)
DECLARE #finalSQL NVARCHAR(1024)
-- Results of the query are put into a table in Demo_DB.
-- So empty it now for the new results.
TRUNCATE TABLE Demo_DB.dbo.index_stats
-- Use a cursor to get a list of all the tables in the instance.
DECLARE database_cursor CURSOR LOCAL FOR
SELECT name
FROM Master.dbo.sysdatabases
WHERE name NOT IN ('master', 'model', 'msdb', 'tempdb')
OPEN database_cursor
FETCH NEXT FROM database_cursor INTO #dbname
WHILE ##FETCH_STATUS = 0
BEGIN
-- Each database will contain the same structue, so I need
-- to create a standard query just changing the database name.
SET #finalSQL = 'INSERT INTO Demo_DB.dbo.index_stats '
-- Sort out the select statement.
SET #finalSQL = #finalSQL + 'SELECT sdb.name, st.name, si.name, si.type_desc, '
SET #finalSQL = #finalSQL + 'si.is_primary_key, si.fill_factor, '
SET #finalSQL = #finalSQL + 'sd.user_scans, sd.last_user_scan, '
SET #finalSQL = #finalSQL + 'sd.user_updates, sd.last_user_update '
-- The 'from' and 'joins' need to be adjusted slightly for each databse.
SET #finalSQL = #finalSQL + 'FROM ' + #dbname + '.sys.tables st '
SET #finalSQL = #finalSQL + 'JOIN ' + #dbname + '.sys.indexes si ON (si.object_id = st.object_id) '
SET #finalSQL = #finalSQL + 'JOIN ' + #dbname + '.sys.dm_db_index_usage_stats sd ON (si.object_id = sd.object_id) '
SET #finalSQL = #finalSQL + 'JOIN ' + #dbname + '.sys.databases sdb ON (sdb.database_id = sd.database_id) ;'
-- Ok, let's run that...
EXEC (#finalSQL)
-- Get the next database in the instance..,
FETCH NEXT FROM database_cursor INTO #dbname
END
CLOSE database_cursor
DEALLOCATE database_cursor
GO
Regards,
JC.

Answer 1

What about concatenation?
Something like this (not reproduced the whole stored procedure, but hopefully you get the gist)
DECLARE #SQL VARCHAR(MAX)
SET #SQL = ''
SELECT #SQL = #SQL +
'INSERT INTO Demo_DB.dbo.index_stats ' +
'SELECT sdb.name, st.name, si.name, si.type_desc, ' +
'si.is_primary_key, si.fill_factor, ' +
'sd.user_scans, sd.last_user_scan, ' +
'sd.user_updates, sd.last_user_update ' +
'FROM ' + name + '.sys.tables st ' +
'JOIN ' + name + '.sys.indexes si ON (si.object_id = st.object_id) ' +
'JOIN ' + name + '.sys.dm_db_index_usage_stats sd ON (si.object_id = sd.object_id) ' +
'JOIN ' + name + '.sys.databases sdb ON (sdb.database_id = sd.database_id) ;'
FROM Master.dbo.sysdatabases
WHERE name NOT IN ('master', 'model', 'msdb', 'tempdb')
SELECT #SQL
(Obviously not EXECing anything at this point).