了解如何编写子查询

问题描述 投票:0回答:1

问题:对于表中的每一行(来自分析表),我试图运行子查询以查找第二个表中的相应行(来自externaldata)。我想我想要一个子查询,但也许有更好的选择。没有链接每个表的列,所以我不能使用连接,唯一的关系是分析表中的数字可能在externaldata表中的开始和结束数字之间。

let IDlist = datatable(value:long)
[
45,
76,
150,
202,
2156,
3004,
5001,
];

// imported from externaldata
let idlookup = datatable(start:long, end:long, name:string)
[
1,100,"bob",
101,105,"susan",
200,1000,"henry",
5000,5004,"clair",
];

//using between doesnt work
idlookup
| where idlist between (start .. end)
| project idlist, name

expected output
45 - bob
76 - bob
150 - no match
202 - henry
2156 - no match
3004 - no match
5001 - clair

上面的查询在between语句不是标量表达式之前不能用作表达式。我希望子查询可以解决这个问题,但是我无法弄清楚语法。非常感谢您的帮助。

subquery between kusto
1个回答
0
投票

这里是一种方式:

let IDlist = datatable(value:long)
[
45,
76,
150,
202,
2156,
3004,
5001,
];
// imported from externaldata
let idlookup = datatable(start:long, end:long, name:string)
[
1,100,"bob",
101,105,"susan",
200,1000,"henry",
5000,5004,"clair",
];
IDlist
| extend dummy = 1
| lookup (idlookup | extend dummy = 1) on dummy
| where value >=start and value <= end
| join kind=rightouter (IDlist) on value
| extend name = iff(isempty( name), "no match", name)
| project name, value = value1
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