While Loop to Iterate through Databases

Question

I was wondering if someone could help me with creating a while loop to iterate through several databases to obtain data from one table from two columns. this is was I have done

Answer 1

CREATE TABLE #T
(dbname sysname NOT NULL PRIMARY KEY,
SumPGCOUNT INT,
CREATED DATETIME)

DECLARE @Script NVARCHAR(MAX) = ''

SELECT @Script = @Script + '

USE ' + QUOTENAME(name) + '
IF EXISTS(SELECT * FROM sys.tables WHERE OBJECT_ID=OBJECT_ID(''dbo.tbldoc''))
  INSERT INTO #T
  SELECT db_name() AS dbname, SUM(PGCOUNT) AS SumPGCOUNT, CREATED 
  FROM dbo.tbldoc
  GROUP BY CREATED;  
  '
FROM sys.databases 
WHERE state=0 AND user_access=0 and has_dbaccess(name) = 1
 AND [name] like 'z%' and create_date between '2010-10-17' and '2011-01-15'
ORDER BY [name]

IF (@@ROWCOUNT > 0)
 BEGIN
 --PRINT @Script
 EXEC (@Script)
 SELECT * FROM #T
 END

 DROP TABLE #T