Need to run select statement across all databases

Question

I am trying to run a query like the one below across multiple databases

select ParamValue from Table1 where paramname = 'SYSTEM_LICENSE'

Each DB is named something like the one below and some DB should be excluded.

"Customer_123"

I looked at using sp_MSforeachdb but it isn't supported and it wasn't working well. I tried figuring out how to write a cursor but was unsuccessful. At this point just looking for some help from someone who can actually write what I am looking to do.

Answer 1

Here's the "do something on each db" template I use, slightly adapted to your example:

--Create a table to hold the query results
CREATE TABLE #licenselist
    (dbid smallint, dbname sysname, system_license varchar(99));

DECLARE @fixedname nvarchar(150);

--Include or exclude whatever databases you want
DECLARE dbCursor CURSOR FOR
    SELECT REPLACE(QUOTENAME(name),'''','''''') --For db names with annoying characters
    FROM master.sys.databases
    WHERE state_desc = 'ONLINE'
    AND HAS_DBACCESS(name) = 1                  --Added at @SolomonRutzky's suggestion
    AND name NOT IN ('master','msdb','model','tempdb');

OPEN dbCursor;
FETCH NEXT FROM dbCursor INTO @fixedname;

WHILE @@FETCH_STATUS = 0   
BEGIN   
       EXEC ('USE ' + @fixedname + ';' + 
        'INSERT INTO #licenselist
         SELECT DB_ID() as dbid, DB_NAME() as dbname, ParamValue as system_license
         FROM Table1 
         WHERE paramname = ''SYSTEM_LICENSE'';');

       FETCH NEXT FROM dbCursor INTO @fixedname;
END;   

CLOSE dbCursor;
DEALLOCATE dbCursor;

SELECT * FROM #licenselist 

DROP TABLE #licenselist

EDIT: streamlined a bit, removed the raw @dbname variable and instead fixed it in the original query.

Answer 2

Thanks again, slightly modified to only query the DB I wanted and output only results with YES.

--Create a table to hold the query results
CREATE TABLE #licenselist
    (dbname sysname, system_license varchar(99));

DECLARE @dbname SYSNAME;
DECLARE @fixedname nvarchar(150);

--Include or exclude whatever databases you want
DECLARE dbCursor CURSOR FOR
    SELECT name FROM master.sys.databases
    WHERE DATABASEPROPERTYEX(name, 'Status') = 'ONLINE'
    AND name like 'SOMETHING_%'
    AND name not like '%_SOMETHINGELSE'
    --AND name NOT IN ('master','msdb','model','tempdb');

OPEN dbCursor;
FETCH NEXT FROM dbCursor INTO @dbname;

WHILE @@FETCH_STATUS = 0   
BEGIN   
       --Fix for invalid characters in DB names
       SELECT @fixedname = REPLACE(QUOTENAME(@dbname),'''','''''');     
       EXEC ('USE ' + @fixedname + ';' + 
        'INSERT INTO #licenselist
         SELECT DB_NAME() as dbname, ParamValue as system_license
         FROM TABLE1 
         WHERE paramname = ''STRING_VALUE'';');

       FETCH NEXT FROM dbCursor INTO @dbname;
END;   

CLOSE dbCursor;
DEALLOCATE dbCursor;

SELECT *
FROM #licenselist
where system_license='YES'
ORDER by dbname desc

DROP TABLE #licenselist