How to drop multiple databases in SQL Server

39,438

Solution 1

this is easy...

use master
go
declare @dbnames nvarchar(max)
declare @statement nvarchar(max)
set @dbnames = ''
set @statement = ''
select @dbnames = @dbnames + ',[' + name + ']' from sys.databases where name like 'name.of.db%'
if len(@dbnames) = 0
    begin
    print 'no databases to drop'
    end
else
    begin
    set @statement = 'drop database ' + substring(@dbnames, 2, len(@dbnames))
    print @statement
    exec sp_executesql @statement
    end

Solution 2

Why not just do this instead?

USE master;
Go
SELECT 'DROP DATABASE ['+ name + ']' 
FROM sys.databases WHERE name like '_database_name_%';
GO

Capture the output of that resultset and then paste it into another query window. Then run that. Why write all this TSQL cursor code?

"When you have a hammer, everything looks like a nail!"..

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39,438
Gargravarr
Author by

Gargravarr

Updated on July 31, 2020

Comments

  • Gargravarr
    Gargravarr almost 4 years

    Just to clarify, ths isn't really a question, more some help for people like me who were looking for an answer.
    A lot of applications create temp tables and the like, but I was surprised when Team Foundation Server created 80+ databases on my test SQL Server. TFS didn't install correctly, and kindly left me to clear up after it. Since each database had a naming convention, rather than delete each database by hand, I remembered how to use cursors and have written what I view to be the most unwise piece of T-SQL ever:

       CREATE TABLE #databaseNames (name varchar(100) NOT NULL, db_size varchar(50), owner varchar(50), dbid int, created date, status text, compatibility_level int);
    INSERT #databaseNames
        exec sp_helpdb;
    
    DECLARE dropCur CURSOR FOR
        SELECT name FROM #databaseNames WHERE name like '_database_name_%';
    OPEN dropCur;
    DECLARE @dbName nvarchar(100);
    FETCH NEXT FROM dropCur INTO @dbName;
    DECLARE @statement nvarchar(200);
    WHILE @@FETCH_STATUS = 0
    BEGIN
        SET @statement = 'DROP DATABASE ' + @dbName;
        EXEC sp_executesql @statement;
        FETCH NEXT FROM dropCur INTO @dbName;
    END
    CLOSE dropCur;
    DEALLOCATE dropCur;
    DROP TABLE #databaseNames;
    

    It goes without saying that using cursors like this is probably really dangerous, and should be used with extreme caution. This worked for me, and I haven't seen any further damage to my database yet, but I disclaim: use this code at your own risk, and back up your vital data first!
    Also, if this should be deleted because it's not a question, I understand. Just wanted to post this somewhere people would look.