Need to convert SQL server code to Mysql code

[kalyan navuluri]

Need to convert the following SQL Server code to Mysql code....

create procedure leaves()
begin
update leaves set EarnedLeaves =1-leaves where Monthname(Month)='january'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='january'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='february'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='february'and leaves.Empid=e.Empid)+1)end case) where Monthname(Month)='february'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='february'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='march'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='march'and leaves.Empid=e.Empid)+1)end case) where Monthname(Month)='march'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='march'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='april'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='april'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='april'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='april'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='may'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='may'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='may'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='may'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='june'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='june'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='june'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='june'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='july'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='july'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='july'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='july'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='august'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='august'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='august'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='august'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='september'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='september'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='september'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='september'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='october'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='october'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='october'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='october'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='november'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='november'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='november'
update leaves set EarnedLeaves =(select case when((select isnull(e.earnedleaves,0) from leaves e where e.Monthname(Month)='november'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='december'and leaves.Empid=e.Empid)+1)<0 then 0 else ((select isnull(e.earned_leaves,0) from leaves e where e.Month='jan'and leaves.Empid=e.Empid)-(select isnull(e.leaves,0) from leaves e where e.Monthname(Month)='december'and leaves.Empid=e.Empid)+1)end case)where Monthname(Month)='december'
end