How to delete all rows from all tables in a SQL Server database?

Question

How to delete all rows from all tables in a SQL Server database?

Answer 1

This answer builds on Zach Smith's answer by resetting the identity column as well:

1. Disabling all constraints
2. Iterating through all tables except those you choose to exclude
3. Deletes all rows from the table
4. Resets the identity column if one exists
5. Re-enables all constraints

Here is the query:

-- Disable all constraints in the database
EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"

declare @catalog nvarchar(250);
declare @schema nvarchar(250);
declare @tbl nvarchar(250);
DECLARE i CURSOR LOCAL FAST_FORWARD FOR select
                                        TABLE_CATALOG,
                                        TABLE_SCHEMA,
                                        TABLE_NAME
                                        from INFORMATION_SCHEMA.TABLES
                                        where
                                        TABLE_TYPE = 'BASE TABLE'
                                        AND TABLE_NAME != 'sysdiagrams'
                                        AND TABLE_NAME != '__RefactorLog'
                                        -- Optional
                                        -- AND (TABLE_SCHEMA = 'dbo')

OPEN i;
FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
WHILE @@FETCH_STATUS = 0
    BEGIN
        DECLARE @sql NVARCHAR(MAX) = N'DELETE FROM [' + @catalog + '].[' + @schema + '].[' + @tbl + '];'
        /* Make sure these are the commands you want to execute before executing */
        PRINT 'Executing statement: ' + @sql
        --EXECUTE sp_executesql @sql

        -- Reset identity counter if one exists
        IF ((SELECT OBJECTPROPERTY( OBJECT_ID(@catalog + '.' + @schema + '.' + @tbl), 'TableHasIdentity')) = 1)
        BEGIN
            SET @sql = N'DBCC CHECKIDENT ([' + @catalog + '.' + @schema + '.' + @tbl + '], RESEED, 0)'
            PRINT 'Executing statement: ' + @sql
            --EXECUTE sp_executesql @sql
        END     

        FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
    END
CLOSE i;
DEALLOCATE i;

-- Re-enable all constraints again
EXEC sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"