Looping in MySQL Stored Procedure

Hi Friends,

How to do the following Loop Coding in MYSQL STORED PROCEDURE ?

RS_prd = select * from tblprdsky
do until RS_prd.eof

          RS_cst = update tblcst SET SAPLID=RS_prd("SAPLID") where Prdcde=RS_prd("Prdcde") AND PrdValue=RS_prd("vlu")


RS_prd.movenext
loop

Expecting your valuable reply.