Project columns based on list of column names in Kusto / Data Explorer

Question

I have a Kusto table that have hundreds of columns. About half of the columns contain dates. Each date column has the word 'date' in it's name (For example: 'createdDate'). I would like to return only columns that contain "date" in the column name.

(Of note, the values in the "date" columns are strings)

I am trying to do the following:

let T1 = datatable (col1:string, col2:string, Date1:string, Date2:string)[
"abc", "def", "2021-11-3", "2021-11-4",
"ghi", "jkl", "2021-11-5", "2021-11-6",
"mno", "pqr", "2021-11-7", "2021-11-8",
"stu", "v", "2021-11-9", "2021-11-10",
"wx", "yz", "2021-11-11", "2021-11-12"];
let ColswithDates = T1
| getschema 
| where ColumnName contains "date";
T1 | project ColswithDates

Answer 1

Use "project-keep" operator

let T1 = datatable (col1:string, col2:string, Date1:string, Date2:string)[
"abc", "def", "2021-11-3", "2021-11-4",
"ghi", "jkl", "2021-11-5", "2021-11-6",
"mno", "pqr", "2021-11-7", "2021-11-8",
"stu", "v", "2021-11-9", "2021-11-10",
"wx", "yz", "2021-11-11", "2021-11-12"];
let ColswithDates = T1
| getschema 
| where ColumnName contains "date";
T1 | project-keep *Date*

Date1	Date2
2021-11-3	2021-11-4
2021-11-5	2021-11-6
2021-11-7	2021-11-8
2021-11-9	2021-11-10
2021-11-11	2021-11-12