optimizing the code - sql

Question

I have written this code for small database but know the database size has increased,it is showing timeout error.plz help in optimizing it
Below is the code:-
IF OBJECT_ID('Temp_expo') is not null
begin
drop table Temp_expo
end
set #query3 = 'SELECT SPCT_ID_REL_LOW,SPCT_ID_REL_HIGH,ROW_NUMBER() over (order by PDBC_PFX) as TempId
INTO Temp_expo
FROM ['+ #FCTServer +'].['+#FCTDBName+'].dbo.CMC_SPCT_SUPP_CONV
where SPCT_ID_REL_LOW <> '''' and SPCT_ID_REL_HIGH <> '''''
exec (#query3)
Select #minCount= min(TempId) from Temp_expo
Select #maxCount= max(TempId) from Temp_expo
create table #ICD9SPCT
(
ICD9Code varchar(200)
}
while #minCount<=#maxCount
begin
select #low=SPCT_ID_REL_LOW,#high=SPCT_ID_REL_HIGH
from Temp_expo
where TempId=#minCount
group by SPCT_ID_REL_LOW,SPCT_ID_REL_HIGH
set #loworder = (select ISNULL(OrderId,0) from FCT_ICD9_Diag_ORDER where ICD9=#low)
set #highorder = (select ISNULL(OrderId,0) from FCT_ICD9_Diag_ORDER where ICD9=#high)
insert into #ICD9SPCT
select ICD9 from FCT_ICD9_Diag_ORDER ordert
left join #ICD9SPCT icdorder on ordert.ICD9 = icdorder.ICD9Code
where OrderId between #loworder and #highorder and icdorder.ICD9Code is null
set #minCount = #minCount+1;
end

Answer 1

If this is for SQL SERVER, there are some basic tips you can try:
USE: WITH (NOLOCK) after every select you use.
i.e.
select ICD9 from FCT_ICD9_Diag_ORDER ordert WITH (NOLOCK)
left join #ICD9SPCT icdorder on ordert.ICD9 = icdorder.ICD9Code
where OrderId between #loworder and #highorder and icdorder.ICD9Code is null
You can also try to change your temp tables to variable tables, by just changing the # for an # like :
create table #ICD9SPCT
(
ICD9Code varchar(200)
}
Still, the WHILE loop you are using may be the primary cause of your problem.