How truncate time while querying documents for date comparison in Cosmos Db - azure

Question

I have document contains properties like this
{
"id":"1bd13f8f-b56a-48cb-9b49-7fc4d88beeac",
"name":"Sam",
"createdOnDateTime": "2018-07-23T12:47:42.6407069Z"
}
I want to query a document on basis of createdOnDateTime which is stored as string.
query e.g. -
SELECT * FROM c where c.createdOnDateTime>='2018-07-23' AND c.createdOnDateTime<='2018-07-23'
This will return all documents which are created on that day.
I am providing date value from date selector which gives only date without time so, it gives me problem while comparing date.
Is there any way to remove time from createdOnDateTime property or is there any other way to achieve this?

Answer 1

CosmosDB clients are storing timestamps in ISO8601 format and one of the good reasons to do so is that its lexicographical order matches the flow of time. Meaning - you can sort and compare those strings and get them ordered by time they represent.
So in this case you don't need to remove time components just modify the passed in parameters to get the result you need. If you want all entries from entire date of 2018-07-23 then you can use query:
SELECT * FROM c
WHERE c.createdOnDateTime >= '2018-07-23'
AND c.createdOnDateTime < '2018-07-24'
Please note that this query can use a RANGE index on createdOnDateTime.

Answer 2

Please use User Defined Function to implement your requirement, no need to update createdOnDateTime property.
UDF：
function con(date){
var myDate = new Date(date);
var month = myDate.getMonth()+1;
if(month<10){
month = "0"+month;
}
return myDate.getFullYear()+"-"+month+"-"+myDate.getDate();
}
SQL：
SELECT c.id,c.createdOnDateTime FROM c where udf.con(c.createdOnDateTime)>='2018-07-23' AND udf.con(c.createdOnDateTime)<='2018-07-23'
Output :
Hope it helps you.