使用 ServiceStack OrmLite 进行复杂的 JOIN

Question

我如何表达下面的查询（来自this question）：

SELECT c.*, p1.*
FROM customer c
JOIN purchase p1 ON (c.id = p1.customer_id)
LEFT OUTER JOIN purchase p2 ON (c.id = p2.customer_id AND 
    (p1.date < p2.date OR p1.date = p2.date AND p1.id < p2.id))
WHERE p2.id IS NULL;

使用 OrmLite Select 和 Join API？

Answer 1

不幸的是，您的多表自表连接过于复杂，无法在 OrmLite 的 Typed API 中表达，因此您需要下拉到自定义 SQL，例如：

var results = db.Select<Tuple<Customer,Purchase>>(@"SELECT c.*, 0 EOT, p1.*
    FROM customer c
    JOIN purchase p1 ON (c.id = p1.customer_id)
    LEFT OUTER JOIN purchase p2 ON (c.id = p2.customer_id AND 
        (p1.date < p2.date OR p1.date = p2.date AND p1.id < p2.id))
    WHERE p2.id IS NULL;");

results.PrintDump();

我创建了一个Live Example of this you can play with on Gistlyn。