在PostgreSQL中加入两个查询

Question

我想将两个查询连接到一个查询中。

在第一个查询中检索到的是列为resourceindex的表，它按升序排序：

String loadRates = "SELECT * FROM ratings WHERE userindex="
            + uindex
            + " ORDER BY rank  DESC";

在第二个查询中，应检索的是resourceindexes：

行

String loadResources = "SELECT * FROM resourceinfo WHERE resourceindex = "
                    + rs.getInt("resourceindex");

如何将这些组合成一个查询？

Answer 1

SELECT ri.* FROM resourceinfo ri, ratings r
WHERE ri.resourceindex = r.resourceindex AND r.userindex = ?
ORDER BY r.rank DESC

Answer 2

试试这个：

"SELECT * FROM public.resourceinfo, public.ratings WHERE "
                + "ratings.resourceindex = resourceinfo.index AND ratings.userindex = " 
                + uindex
                + "ORDER BY ratings.rank DESC";