如何使用RAISEERROR语句？

Question

这是非常基本的东西，但我无法理解，手册没有帮助：

declare @rule int =
    (select id from menu_availability_rules
        where (daily_serving_start = null or
            (daily_serving_start is null and null is null)) and
            (daily_serving_end = null or
            (daily_serving_end is null and null is null)) and
            (weekly_service_off = 3 or
            (weekly_service_off is null and 3 is null)) and
            (one_time_service_off = null or
            (one_time_service_off is null and null is null)));

        print @rule;
        -- syntax error here --\/
        if (@rule is not null) raiseerror ('test error', 42, 42);

        if @rule is not null
        begin
            delete from menu_availability
            where menu_id = 5365 and rule_id = @rule

            delete from menu_availability_rules
            where (daily_serving_start = null or
                (daily_serving_start is null and null is null)) and
                (daily_serving_end = null or
                (daily_serving_end is null and null is null)) and
                (weekly_service_off = 3 or
                (weekly_service_off is null and 3 is null)) and
                (one_time_service_off = null or
                (one_time_service_off is null and null is null))
            and not exists
                (select rule_id from menu_availability
                where rule_id = @rule)
        end

为什么会出现语法错误？我该怎么写呢？为了调试目的，我需要抛出错误，只是为了确保代码到达条件分支。

我可以用raiseerror取代select 1 / 0，我会得到我需要的东西，但为什么我不能正常做到？

Answer 1

正确的名称是RAISERROR。