postgresql 选择进入

Question

我正在尝试创建 postgres 脚本，但我无法从表格行的 max() 函数返回值。

这是脚本的重要部分：

                DECLARE index SMALLINT;
                SELECT max(bag_index) INTO index FROM booking_bags 
                WHERE bid = NEW.bid AND 
                      pid = NEW.pid AND 
                      fid = NEW.fid AND 
                      ordered_bag_id = NEW.ordered_bad_id;

我收到此错误：类型名称无效“max(bag_index) INTO index FROM booking_bags 在哪里出价“ LINE 6: SELECT max(bag_index) INTO index FROM bo...

有人知道如何将 max 函数中的值转换为声明的变量吗？

Answer 1

            DECLARE @index SMALLINT;
            SELECT @index = max(bag_index) FROM booking_bags 
            WHERE bid = NEW.bid AND 
                  pid = NEW.pid AND 
                  fid = NEW.fid AND 
                  ordered_bag_id = NEW.ordered_bad_id;