基本要求是创建以下格式的订单号:
(M)M-SSS
其中 MM 代表当前月份,SSSS 代表该月的订单顺序。例如,1-002 代表一月份提交的第二个订单。
使用触发器,我希望自动增量和插入能够透明地工作。
不幸的是,我已经很久没有接触过存储过程了,这是我第一次接触 postgresql。任何指向正确方向的帮助将不胜感激。
更新:这是使用@peterm代码的最终实现
-- The trigger
CREATE TRIGGER add_order_number
BEFORE INSERT ON orders FOR EACH ROW
EXECUTE PROCEDURE order_number_update();
-- The trigger function
CREATE FUNCTION order_number_update() RETURNS TRIGGER AS $$
DECLARE
next_order TEXT;
BEGIN
-- get the next order number
SELECT INTO next_order CONCAT(CAST(DATE_PART('MONTH', CURRENT_DATE) AS VARCHAR(2)),
'-',
LPAD(CAST(COALESCE(CAST(RIGHT(MAX(order_number), 3) AS INT), 0) + 1 AS VARCHAR(3)), 3, '0'))
FROM orders
WHERE CAST(LEFT(order_number, STRPOS(order_number, '-') - 1) AS INT) = DATE_PART('MONTH', CURRENT_DATE);
-- update the field
NEW.order_number = next_order;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
注意:通过将更新添加为 BEFORE INSERT 触发器,它会以完全透明且可预测的方式运行,就像普通的 SERIAL 或 BIGSERIAL 字段一样。
最佳答案
您正在寻找这样的东西吗?
-- Next No calculated for current month
SELECT CONCAT(CAST(DATE_PART('MONTH', CURRENT_DATE) AS VARCHAR(2)),
'-',
LPAD(CAST(COALESCE(CAST(RIGHT(MAX(order_no), 4) AS INT), 0) + 1 AS VARCHAR(4)), 4, '0')) next_no
FROM orders
WHERE CAST(LEFT(order_no, STRPOS(order_no, '-') - 1) AS INT) = DATE_PART('MONTH', CURRENT_DATE)
;
输出:
| NEXT_NO |
-----------
| 5-0001 |
假设有一条order_no
= '1-0001'的记录
-- Next No for January
SELECT CONCAT(CAST(DATE_PART('MONTH', DATE '2013-01-01') AS VARCHAR(2)),
'-',
LPAD(CAST(COALESCE(CAST(RIGHT(MAX(order_no), 4) AS INT), 0) + 1 AS VARCHAR(4)), 4, '0')) next_no
FROM orders
WHERE CAST(LEFT(order_no, STRPOS(order_no, '-') - 1) AS INT) = DATE_PART('MONTH', DATE '2013-01-01')
;
输出:
| NEXT_NO |
-----------
| 1-0002 |
<强> SQLFiddle
关于postgresql - postgresql中的自定义自增字段(发票/订单号),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16598959/