SQL statement to auto-increment the number of fields

Assume that the field to be numbered is: BH

The table's primary key is: BSM,

Update tablename

Set bH = cast (X. rownumber as varchar (10) from (select rownumber = row_number () over (order by BSM), * From tablename) x

Where tablename. BSM = x. BSM

It can be understood in two steps,

Step 1: first filter out a temporary table. This table adds a rownunmber field, which is the serial number of each row,

Step 2: Associate the original table with the temporary table with BSM, and update the rownumber field in the temporary table to the column to be updated.

The row_number () function is used. If it is not used, it can be Baidu.