DECLARE DataClean CURSORFOR    SELECT  a.name AS t_name ,            b.name AS c_name ,            c.DATA_TYPE    FROM    sys.tables a            JOIN sys.columns b ON b.object_id = a.object_id            JOIN INFORMATION_SCHEMA.COLUMNS c ON b.name = c.COLUMN_NAME            AND a.name = c.TABLE_NAMEOPEN DataCleanDECLARE @t_name VARCHAR(100) ,        @c_name VARCHAR(100) ,        @DATA_TYPE VARCHAR(100) FETCH NEXT FROM DataClean INTO @t_name, @c_name, @DATA_TYPEWHILE @@FETCH_STATUS = 0     BEGIN                PRINT ('ALTER TABLE ' + @t_name + ' ALTER COLUMN  ' + @c_name+ '  NVARCHAR(2500)')        EXEC ('ALTER TABLE '+@t_name+ ' ALTER COLUMN  '+ @c_name+'  NVARCHAR(2500)')        PRINT ( '表:' + @t_name + '--字段:' + @c_name + '--修改成功' )            FETCH NEXT FROM DataClean INTO @t_name, @c_name, @DATA_TYPE    END                                  --关闭游标CLOSE DataClean                        --释放资源DEALLOCATE DataClean