HTTP Status 500 – Internal Server Error Type Exception Report Message Request processing failed; nested exception is org.apache.ibatis.exceptions.PersistenceException: Description The server encountered an unexpected condition that prevented it from…
join on and vs join on where SELECT * FROM Orders LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID WHERE Orders.ID = 12345 SELECT * FROM Orders LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID AND Orders.ID = 12345 http://stackoverflow.com/qu…
有一个需求表(demand),每一记录就是一条需求:另外有一个报价表(quotation),每一条记录是对需求记录的报价详情. 需求表: 报价表: 我现在想得到每条需求的信息以及有多少人报价了,我们可以使用 SELECT v9_demand.*, ( SELECT count(q.id) FROM v9_quotation q where q.dem_id = v9_demand.id ) AS qnum FROM v9_demand ORDER BY id ASC; 呵呵,每天记录一点点,加油…