Kusto KQL 等价于 LIKE CONCAT 列的值 (mysql)

Question

I'm trying to translate the following MySQL (v5.6) query:

SELECT name FROM world WHERE capital LIKE CONCAT(name, '%city')

into Kusto KQL, but the following doesn't work:

world | where capital matches regex strcat(name,".*city") | project name

Probably since the the matches regex takes only a string value, and concat(name,".*city") is a column.

Even the following doesn't work:

world | extend a =  strcat(name, ".*City") | where capital matches regex a

Any suggestions to how I can translate this query to KQL?

Answer 1

The argument to matches regex must be a scalar string constant, and can depend on row context.

If you can make any assumptions on the actual data, you may not need to use a regular expression at all, and have a wide set of string operators to choose from (depending on the data and the requirement, of course): https://docs.microsoft.com/en-us/azure/kusto/query/datatypes-string-operators

For example:

let world = datatable(capital:string)
[
    "Belize City",
    "Jeruslam",
    "Mexico City",
    "Tulum",
    "NotARealCity"
]
;
world
| extend _ends_with = capital endswith "city",
               _has = capital has "city",
          _contains = capital contains "city"

Results with:

| capital      | _ends_with | _has | _contains |
|--------------|------------|------|-----------|
| Belize City  | 1          | 1    | 1         |
| Jeruslam     | 0          | 0    | 0         |
| Mexico City  | 1          | 1    | 1         |
| Tulum        | 0          | 0    | 0         |
| NotARealCity | 1          | 0    | 1         |