declare crReq cursor for select LastName, MiddleName, FirstName, BirthDate from Table
for update of ErrCode

  open crReq
               
  fetch crReq into @ln, @mn, @fn, @bd

  while @@sqlstatus= 0     
  begin
    select @cnt = count(*) from Clients where LastName = @ln and MiddleName = @mn 
              and FirstName = @fn and BirthDate = @bd

    if @cnt> 1  ErrCode =  1 
    if @cnt< 1  ErrCode =  2 

    if @cnt= 1 
    begin
       ...
       Действия
       ...
    end

    fetch crReq into @ln, @mn, @fn, @bd
  end

close crReq
deallocate cursor crReq

declare crReq cursor for select ID, LastName, MiddleName, FirstName, BirthDate from Table
for update of ErrCode

  open crReq
               
  fetch crReq into @rid, @ln, @mn, @fn, @bd

  while @@sqlstatus= 0     
  begin
    select @cnt = count(*) from Clients where LastName = @ln and MiddleName = @mn 
              and FirstName = @fn and BirthDate = @bd

    if @cnt> 1  update gTabRequisit_loader set ErrCode =  1  where ReqId = @rid
    if @cnt< 1  update gTabRequisit_loader set ErrCode =  2  where ReqId = @rid

    if @cnt= 1 
    begin
       ...
       Действия
       ...
    end

    fetch crReq into @rid, @ln, @mn, @fn, @bd
  end

close crReq
deallocate cursor crReq