概述

ORDER BY子句调整别名代表的数据行的顺序。

语法

ORDER BY <expression> <string>, <expression> <string>, ...

• <expression>是排序依据；如果使用了多个别名，它们必须同源，此时按照从左到右的顺序逐级进行排序
• <string>是排序方式，支持ASC（升序）或DESC（降序），大小写不敏感，忽略时为ASC

例如，对以下路径查询产生的数据流进行多重排序。先按照终点n的半径大小降序排列，半径大小相同的再按照终点n的_uuid大小升序排列:

n([4, 2]).e().n(as n) as path
order by n.radius desc, n
return path

示例

示例图集

在一个空图集中，依次运行以下各行语句创建示例图集：

create().node_schema("student").node_schema("course")
create().node_property(@*, "name").node_property(@student, "age", int32).node_property(@course, "credit", int32)
insert().into(@student).nodes([{_id:"S001", _uuid:1, name:"Jason", age:25}, {_id:"S002", _uuid:2, name:"Lina", age:23}, {_id:"S003", _uuid:3, name:"Eric", age:24}, {_id:"S004", _uuid:4, name:"Emma", age:26}, {_id:"S005", _uuid:5, name:"Pepe", age:24}])
insert().into(@course).nodes([{_id:"C001", _uuid:6, name:"French", credit:4}, {_id:"C002", _uuid:7, name:"Math", credit:5}])
insert().into(@default).edges([{_uuid:1, _from_uuid:1, _to_uuid:6}, {_uuid:2, _from_uuid:2, _to_uuid:6}, {_uuid:3, _from_uuid:3, _to_uuid:6}, {_uuid:4, _from_uuid:2, _to_uuid:7}, {_uuid:5, _from_uuid:3, _to_uuid:7}, {_uuid:6, _from_uuid:4, _to_uuid:7}, {_uuid:7, _from_uuid:5, _to_uuid:7}])

分组+排序

本例查询“课程-[]-学生”1步路径，按课程分组后，统计各组内学生的数量，再按学生数量降序排列：

n({@course} as a).e().n({@student})
group by a
with count(a) as b
order by b desc 
return table(a.name, b)

| a.name | b |
|--------|---|
| Math   | 4 |
| French | 3 |

多级排序

本例查询“课程-[]-学生”1步路径，按课程的credit属性升序排列后，再按学生的age属性降序排列，返回返回路径中点和边的全部信息：

n({@course} as a).e().n({@student} as b) as p
order by a.credit, b.age desc 
return p{*}

French <---- Jason
French <---- Eric
French <---- Lina
Math <---- Emma
Math <---- Eric
Math <---- Pepe
Math <---- Lina