Add the SQL & amp; MySQL query field as the row number

SQL & MySQL query adds a field as the row number. SQL: select row_number () over (order by col desc), * from table; the function "row_number" must have an OVER clause using ORDER, the automatic values are arranged by the field col: www.2cto.com MySQL: SET @ r = 0; SELECT @ r: = IFNULL (@ r, 0) + 1 AS rownum, table. * FROM table order by col DESC; Unlike SQL, fields are added to the loop. If you want to query all rows, you must add the table name table. *, if a field is obtained, it is not required, col1, col2...