如何移除Kusto折线图中多余的连接线？

问题原因 #

你的查询执行union后，Room1和Room4两个Place各有两条记录，分别对应String字段的两个不同值（"Hello Rithwik"和"Winner"）。启用series=String后，这两个值会被作为独立的折线系列绘制，而你隐藏了图例，所以看不到是两条不同的线，误以为是多余的线条。

解决方案 #

方案一：聚合去重（推荐） #

通过summarize对相同Place的记录做聚合，消除重复的系列：

let data = datatable(Place:string, Date:string, Stage_Num:int, String:string)
[
    "Room1", "1/30/23", 3, "Winner",
    "Room4", "2/4/23", 3, "Winner",
];
let mytable = datatable(Place:string, Date:string, Stage_Num:int)
[
  "Room1", "1/30/23", 3,
  "Room2", "2/1/23",  1,
  "Room3", "2/3/23",  2,
  "Room4", "2/4/23",  3,
]
;
mytable
| project Place, Date, Stage_Num, String = "Hello Rithwik"
| union (data)
| project Place, Date, Stage_Num, String
// 聚合相同Place的记录，这里Stage_Num值相同，取max/first均可
| summarize Stage_Num = max(Stage_Num) by Place, Date
| order by Date asc
| render linechart with ( 
    legend = hidden,
    ymin=0, ymax=5,
    xcolumn=Place, xaxis=linear, ycolumns=Stage_Num, ytitle="Stage", xtitle="Place"
)
;

方案二：过滤多余系列 #

如果你只需要保留其中一个String系列，可以添加过滤条件：

let data = datatable(Place:string, Date:string, Stage_Num:int, String:string)
[
    "Room1", "1/30/23", 3, "Winner",
    "Room4", "2/4/23", 3, "Winner",
];
let mytable = datatable(Place:string, Date:string, Stage_Num:int)
[
  "Room1", "1/30/23", 3,
  "Room2", "2/1/23",  1,
  "Room3", "2/3/23",  2,
  "Room4", "2/4/23",  3,
]
;
mytable
| project Place, Date, Stage_Num, String = "Hello Rithwik"
| union (data)
| project Place, Date, Stage_Num, String
// 只保留需要的系列，这里示例保留"Hello Rithwik"
| where String == "Hello Rithwik"
| order by Date asc
| render linechart with ( 
    legend = hidden,
    ymin=0, ymax=5,
    xcolumn=Place, xaxis=linear, ycolumns=Stage_Num, ytitle="Stage", xtitle="Place", series=String
)
;

补充说明 #

如果你的业务逻辑中，同一个Place确实需要区分不同String的Stage_Num，那可以保留series=String并取消图例隐藏，这样就能清晰看到两个系列的区别，避免误以为是多余线条。

内容的提问来源于stack exchange，提问作者chocalaca