Question

我正在编写一个程序来显示给定状态下的所有客户。用户将输入两个字符缩写（exp：CA，PA），它将显示处于给定状态的所有客户。如果没有客户处于给定状态（如'GA'），我需要打印一条消息。我下面的内容是工作，但我觉得可能有一种更简单/更有效的方法。任何反馈都是受欢迎的;我很困惑的一个方面是如何清理我打印出来的消息。另请注意，这是为了完成学校作业。

到目前为止这是我的程序：

    create procedure display_customer_state
(@state char (2))
as 
begin

--begin cursor
declare customer_state_check cursor for
select address_state
from customer
for read only

declare @entered_cust_state as char(2), @state_count as int 
set @state_count = 0
open customer_state_check
fetch customer_state_check into @entered_cust_state

    while @@FETCH_STATUS = 0
    begin

        if @entered_cust_state = @state
        begin
        set @state_count = @state_count+1
        end

fetch customer_state_check into @entered_cust_state

end
close customer_state_check
deallocate customer_state_check
--cursor end

if @state_count = 0
begin
print 'sorry, there are 0 customers in '
print @state
end

select first_name,last_name, primary_address, address_zip_code, address_state
from customer
where address_state = lower(@state)

end

Answer 1

Ouch - 您当然不需要游标来计算与表中的过滤器匹配的记录数。过滤后的计数应该能够替换整个游标：

declare @state_count as int = 0;

select @state_count = COUNT(numaddress_state)
from customer
where customer_state_check = @state;

如果没有找到结果，如何编写SQL过程来打印出消息

1 个答案: