Conditional row update

[smpa01]

I have a Kusto table like this, how can I update certain fields with where condition while doing inline ingestion

id	name	city	salary	tel
1	sam
2	john
3	tom

I can do the following. But by doing so, I need to provide the values for whole row; which i don't want. Also, I want to to be selective in picking columns to update

It does not have to be inline ingest thpough.

//KQL
.ingest inline into table emp <|
1,'sam','london','1000', null
,2,'john','ny','2000',null

//SQL equivalent
UPADTE dbo.people
SET salary = case id when 1 then 1000
                  id when 2 then 2000 END
 city = case id when 1 then 'london'
                  id when 2 then 'ny' END

Thank you in advance

[v-tangjie-msft · Accepted solution]

Hi @smpa01 ,

1.Create a temporary table with the updated values:

let tempTable = datatable (id:int, name:string, city:string, salary:int, tel:string)
[
    1, 'sam', 'london', 1000, null,
    2, 'john', 'ny', 2000, null
];

2.Merge the temporary table with the original table:

let emp = datatable (id:int, name:string, city:string, salary:int, tel:string)
[
    1, 'sam', '', '', '',
    2, 'john', '', '', '',
    3, 'tom', '', '', ''
];

let updatedEmp = union emp, tempTable
| summarize city = any(city), salary = any(salary), tel = any(tel) by id, name;

.set-or-replace emp <| updatedEmp

This approach allows you to selectively update specific columns without needing to provide values for the entire row. 

Best Regards,

Neeko Tang

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