两个 MATCH 交并差计算之后如何统计数量

[firepation]

• nebula 版本：3.2.0
• 部署方式：分布式
• 安装方式：Docker
• 是否为线上版本：N
• 问题的具体描述：
  对两个 MATCH 结果集进行 UNION、INTERSECT、MINUS 操作之后如何统计结果数
  ，在 2.0.0 版本中，可通过 (MATCH (expression) UNION MATCH(expression)) | YIELD COUNT(*) 来实现，在 3.2.0 这个语法不支持，有其他的方式实现吗

[wey]

如果不是 count，直接可以用 UNION

MATCH (n:player)
RETURN n.player.name AS name
UNION
MATCH (n:team)
RETURN n.team.name AS name

+-------------------------+
| name                    |
+-------------------------+
| "Vince Carter"          |
| "Giannis Antetokounmpo" |
| "Damian Lillard"        |
| "Dwight Howard"         |
| "Amar'e Stoudemire"     |
| "Jason Kidd"            |
| "Rudy Gay"              |
| "Dejounte Murray"       |
| "Chris Paul"            |
| "Carmelo Anthony"       |
| "Joel Embiid"           |
| "Steve Nash"            |
| "Rajon Rondo"           |
| "Boris Diaw"            |
| "DeAndre Jordan"        |
| "Ricky Rubio"           |
| "Marc Gasol"            |
| "Klay Thompson"         |
| "JaVale McGee"          |
| "Danny Green"           |
| "Tiago Splitter"        |
| "David West"            |
| "Russell Westbrook"     |
| "Kristaps Porzingis"    |
| "Tim Duncan"            |
| "Tony Parker"           |
| "Cory Joseph"           |
| "Kyrie Irving"          |
| "Paul George"           |
| "Yao Ming"              |
| "Grant Hill"            |
| "Jonathon Simmons"      |
| "Stephen Curry"         |
| "Kevin Durant"          |
| "Blake Griffin"         |
| "Ray Allen"             |
| "Shaquille O'Neal"      |
| "Ben Simmons"           |
| "LaMarcus Aldridge"     |
| "Kyle Anderson"         |
| "Kobe Bryant"           |
| "Dwyane Wade"           |
| "Paul Gasol"            |
| "Tracy McGrady"         |
| "Luka Doncic"           |
| "Marco Belinelli"       |
| "Aron Baynes"           |
| "LeBron James"          |
| "James Harden"          |
| "Manu Ginobili"         |
| "Dirk Nowitzki"         |
| "76ers"                 |
| "Jazz"                  |
| "Lakers"                |
| "Nets"                  |
| "Hornets"               |
| "Mavericks"             |
| "Thunders"              |
| "Suns"                  |
| "Wizards"               |
| "Bulls"                 |
| "Clippers"              |
| "Hawks"                 |
| "Pelicans"              |
| "Cavaliers"             |
| "Celtics"               |
| "Kings"                 |
| "Knicks"                |
| "Pistons"               |
| "Rockets"               |
| "Grizzlies"             |
| "Nuggets"               |
| "Bucks"                 |
| "Magic"                 |
| "Timberwolves"          |
| "Heat"                  |
| "Raptors"               |
| "Spurs"                 |
| "Pacers"                |
| "Trail Blazers"         |
| "Warriors"              |
+-------------------------+
Got 81 rows (time spent 5820/12535 us)

如果需要给结果再处理（比如count），就有点麻烦，不能用集合运算符号，而是用多 MATCH 和 WITH处理。

这里是并集的例子（如果是交集，minus，需要把列表转换为 set 再处理，这里并集我就先列表 + 再去重了）

MATCH (p:player)
WITH collect(p.player.name) AS players
MATCH (t:team)
WITH players + collect(t.team.name) AS playersAndTeamsList
UNWIND playersAndTeamsList AS result
RETURN count(DISTINCT result)


+------------------------+
| count(distinct result) |
+------------------------+
| 81                     |
+------------------------+