Drop all tables whose names begin with a certain string - sql

Question

How can I drop all tables whose names begin with a given string?
I think this can be done with some dynamic SQL and the INFORMATION_SCHEMA tables.

Answer 1

You may need to modify the query to include the owner if there's more than one in the database.
DECLARE #cmd varchar(4000)
DECLARE cmds CURSOR FOR
SELECT 'drop table [' + Table_Name + ']'
FROM INFORMATION_SCHEMA.TABLES
WHERE Table_Name LIKE 'prefix%'
OPEN cmds
WHILE 1 = 1
BEGIN
FETCH cmds INTO #cmd
IF ##fetch_status != 0 BREAK
EXEC(#cmd)
END
CLOSE cmds;
DEALLOCATE cmds
This is cleaner than using a two-step approach of generate script plus run. But one advantage of the script generation is that it gives you the chance to review the entirety of what's going to be run before it's actually run.
I know that if I were going to do this against a production database, I'd be as careful as possible.
Edit Code sample fixed.

Answer 2

SELECT 'DROP TABLE "' + TABLE_NAME + '"'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '[prefix]%'
This will generate a script.
Adding clause to check existence of table before deleting:
SELECT 'IF OBJECT_ID(''' +TABLE_NAME + ''') IS NOT NULL BEGIN DROP TABLE [' + TABLE_NAME + '] END;'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '[prefix]%'

Answer 3

This will get you the tables in foreign key order and avoid dropping some of the tables created by SQL Server. The t.Ordinal value will slice the tables into dependency layers.
WITH TablesCTE(SchemaName, TableName, TableID, Ordinal) AS
(
SELECT OBJECT_SCHEMA_NAME(so.object_id) AS SchemaName,
OBJECT_NAME(so.object_id) AS TableName,
so.object_id AS TableID,
0 AS Ordinal
FROM sys.objects AS so
WHERE so.type = 'U'
AND so.is_ms_Shipped = 0
AND OBJECT_NAME(so.object_id)
LIKE 'MyPrefix%'
UNION ALL
SELECT OBJECT_SCHEMA_NAME(so.object_id) AS SchemaName,
OBJECT_NAME(so.object_id) AS TableName,
so.object_id AS TableID,
tt.Ordinal + 1 AS Ordinal
FROM sys.objects AS so
INNER JOIN sys.foreign_keys AS f
ON f.parent_object_id = so.object_id
AND f.parent_object_id != f.referenced_object_id
INNER JOIN TablesCTE AS tt
ON f.referenced_object_id = tt.TableID
WHERE so.type = 'U'
AND so.is_ms_Shipped = 0
AND OBJECT_NAME(so.object_id)
LIKE 'MyPrefix%'
)
SELECT DISTINCT t.Ordinal, t.SchemaName, t.TableName, t.TableID
FROM TablesCTE AS t
INNER JOIN
(
SELECT
itt.SchemaName AS SchemaName,
itt.TableName AS TableName,
itt.TableID AS TableID,
Max(itt.Ordinal) AS Ordinal
FROM TablesCTE AS itt
GROUP BY itt.SchemaName, itt.TableName, itt.TableID
) AS tt
ON t.TableID = tt.TableID
AND t.Ordinal = tt.Ordinal
ORDER BY t.Ordinal DESC, t.TableName ASC

Answer 4

On Oracle XE this works:
SELECT 'DROP TABLE "' || TABLE_NAME || '";'
FROM USER_TABLES
WHERE TABLE_NAME LIKE 'YOURTABLEPREFIX%'
Or if you want to remove the constraints and free up space as well, use this:
SELECT 'DROP TABLE "' || TABLE_NAME || '" cascade constraints PURGE;'
FROM USER_TABLES
WHERE TABLE_NAME LIKE 'YOURTABLEPREFIX%'
Which will generate a bunch of DROP TABLE cascade constraints PURGE statements...
For VIEWS use this:
SELECT 'DROP VIEW "' || VIEW_NAME || '";'
FROM USER_VIEWS
WHERE VIEW_NAME LIKE 'YOURVIEWPREFIX%'

Answer 5

EXEC sp_MSforeachtable 'if PARSENAME("?",1) like ''%CertainString%'' DROP TABLE ?'
Edit:
sp_MSforeachtable is undocumented hence not suitable for production because it's behavior may vary depending on MS_SQL version.

Answer 6

Here is my solution:
SELECT CONCAT('DROP TABLE `', TABLE_NAME,'`;')
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'TABLE_PREFIX_GOES_HERE%';
And of course you need to replace TABLE_PREFIX_GOES_HERE with your prefix.

Answer 7

I saw this post when I was looking for mysql statement to drop all WordPress tables based on #Xenph Yan here is what I did eventually:
SELECT CONCAT( 'DROP TABLE `', TABLE_NAME, '`;' ) AS query
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'wp_%'
this will give you the set of drop queries for all tables begins with wp_

Answer 8

CREATE PROCEDURE usp_GenerateDROP
#Pattern AS varchar(255)
,#PrintQuery AS bit
,#ExecQuery AS bit
AS
BEGIN
DECLARE #sql AS varchar(max)
SELECT #sql = COALESCE(#sql, '') + 'DROP TABLE [' + TABLE_NAME + ']' + CHAR(13) + CHAR(10)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE #Pattern
IF #PrintQuery = 1 PRINT #sql
IF #ExecQuery = 1 EXEC (#sql)
END

Answer 9

Xenph Yan's answer was far cleaner than mine but here is mine all the same.
DECLARE #startStr AS Varchar (20)
SET #startStr = 'tableName'
DECLARE #startStrLen AS int
SELECT #startStrLen = LEN(#startStr)
SELECT 'DROP TABLE ' + name FROM sysobjects
WHERE type = 'U' AND LEFT(name, #startStrLen) = #startStr
Just change tableName to the characters that you want to search with.

Answer 10

This worked for me.
DECLARE #sql NVARCHAR(MAX) = N'';
SELECT #sql += '
DROP TABLE '
+ QUOTENAME(s.name)
+ '.' + QUOTENAME(t.name) + ';'
FROM sys.tables AS t
INNER JOIN sys.schemas AS s
ON t.[schema_id] = s.[schema_id]
WHERE t.name LIKE 'something%';
PRINT #sql;
-- EXEC sp_executesql #sql;

Answer 11

select 'DROP TABLE ' + name from sysobjects
where type = 'U' and sysobjects.name like '%test%'
-- Test is the table name

Answer 12

SELECT 'if object_id(''' + TABLE_NAME + ''') is not null begin drop table "' + TABLE_NAME + '" end;'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '[prefix]%'

Answer 13

I had to do a slight derivation on Xenph Yan's answer I suspect because I had tables not in the default schema.
SELECT 'DROP TABLE Databasename.schema.' + TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'strmatch%'

Answer 14

In case of temporary tables, you might want to try
SELECT 'DROP TABLE "' + t.name + '"'
FROM tempdb.sys.tables t
WHERE t.name LIKE '[prefix]%'

Answer 15

I would like to post my proposal of the solution which DROP (not just generate and select a drop commands) all tables based on the wildcard (e.g. "table_20210114") older than particular amount of days.
DECLARE
#drop_command NVARCHAR(MAX) = '',
#system_time date,
#table_date nvarchar(8),
#older_than int = 7
Set #system_time = (select getdate() - #older_than)
Set #table_date = (SELECT CONVERT(char(8), #system_time, 112))
SELECT #drop_command += N'DROP TABLE ' + QUOTENAME(SCHEMA_NAME(schema_id)) + '.' + QUOTENAME([Name]) + ';'
FROM <your_database_name>.sys.tables
WHERE [Name] LIKE 'table_%' AND RIGHT([Name],8) < #table_date
SELECT #drop_command
EXEC sp_executesql #drop_command

Answer 16

If your query returns more than one line, you can collect the results and merge them into a query.
declare #Tables as nvarchar(max) = '[schemaName].['
select #Tables =#Tables + TABLE_NAME +'],[schemaName].['
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE='BASE TABLE'
AND TABLE_SCHEMA = 'schemaName'
AND TABLE_NAME like '%whateverYourQueryIs%'
select #Tables = Left(#Tables,LEN(#Tables)-13) --trying to remove last ",[schemaName].[" part, so you need to change this 13 with actual lenght
--print #Tables
declare #Query as nvarchar(max) = 'Drop table ' +#Tables
--print #Query
exec sp_executeSQL #Query

Answer 17

Try following code:
declare #TableLst table(TblNames nvarchar(500))
insert into #TableLst (TblNames)
SELECT 'DROP TABLE [' + Table_Name + ']'
FROM INFORMATION_SCHEMA.TABLES
WHERE Table_Name LIKE 'yourFilter%'
WHILE ((select COUNT(*) as CntTables from #TableLst) > 0)
BEGIN
declare #ForExecCms nvarchar(500) = (select top(1) TblNames from #TableLst)
EXEC(#ForExecCms)
delete from #TableLst where TblNames = #ForExecCms
END
This SQL script is executed without using a cursor.