我是使用pcb命令编辑器写的 这个软件可以生成ooc（一键命令）可以到这个链接下载https://tieba.baidu.com/p/4309477852

为了使本系统适用于函数，没有任何需要命令约制的连锁命令方块

原理：

给玩家新来玩家，为了能有欢迎系统，就要添加tag标签，一个计分板分数，给完后给虚拟玩家计分板加1，如此反复，这样每个玩家都能有不一样的分数

命令：

scoreboard objectives add UID dummy 

#新建计分板UID

scoreboard players add UID UID 0

#初始化虚拟玩家UID在UID计分板中的分数

scoreboard objectives setdisplay list UID

#在点击Tab玩家名字旁边显示计分板UID

scoreboard players add @a UID 0

#初始化玩家UID在UID计分板中的分数

scoreboard players tag @r[score_UID=0,score_UID_min=0] add UID

#选择@r[score_UID=0,score_UID_min=0]的玩家，给它添加UID的标签

scoreboard players operation @a[tag=UID] UID = UID UID

#选择@a[tag=UID]将他的UID设为虚拟玩家UID

execute @a[tag=UID] ~ ~ ~ scoreboard players add UID UID 1

#给虚拟玩家分数添加1（“execute @a[tag=UID] ~ ~ ~  ”≈命令约制只要有这样的玩家才会执行）

execute @a[tag=UID] ~ ~ ~ tellraw @a [{"text":"[UID 欢迎系统] ","color":"gold","bold":false,"italic":false,"underlined":false,"strikethrough":false,"obfuscated":false},{"text":"欢迎欢迎,欢迎新人：","color":"aqua","bold":true,"italic":false,"underlined":false,"strikethrough":false,"obfuscated":false},{"selector":"@a[tag=UID]","color":"red","bold":false,"italic":true,"underlined":true,"strikethrough":false,"obfuscated":false},{"text":"来到我们这，真的太好了！！！","color":"aqua","bold":true,"italic":false,"underlined":false,"strikethrough":false,"obfuscated":false}]

#欢迎文本

scoreboard players tag @a[tag=UID] remove UID

#删除标签UID

如果有哪个指令（例如scoreboard players tag，@r[score_UID=0,score_UID_min=0]）看不懂的，可以评论，我找时间写关于的一篇文章