2在sqlite中加入查询

Question

任何人都可以帮我这个忙，我是数据库和查询的新手。我正在使用sqlite；我的数据库包含2个表。边缘和节点。 表格就像：

nodes
_______________________
NO     name      family
9808   antony    bits
6757   saly      wood



edges
_______________________
ID     Source    Target
1      9808      6757
2      9808      6757
3      6757      9808
4      6757      9808
5      9808      6757

查询应将源和目标替换为“名称和家庭”和“名称和家庭”，然后计算每个边的频率，从而得出以下结果：

Source            target           frequency
"antony bits"     "saly wood"       3
"saly wood"       "antony bits"     2

Answer 1

以.mode column开始，然后运行以下查询：

select a.name||' '||a.family as source, b.name||' '||b.family as target, count() as freq from edges as c
left join nodes as a on c.source = a.NO
left join nodes as b on c.target = b.NO
group by source, target
order by freq desc ;

输出为：

source       target       freq
-----------  ----------   ----------
antony bits  saly wood    3
saly wood    antony bits  2

诀窍是在源列和目标列上双联接表。