String to Date in SQL - sql

Question

Is there a way to quickly convert this date format to DATE in SQL?
{ “date_from”:”22112017”,”date_to”:”22112017”}
This is needed to filter the data between these dates
(There are a lot of conversion entries on the web, but I haven't found that format)
EDIT:
DECLARE #EndDate DATE = CONVERT(VARCHAR, '22112017', 103)
PRINT #EndDate
Error: Conversion failed when converting date and/or time from character string.
WHAT I HAVE:
#StartDate = '22112017'
#EndDate = '22112020'
WHAT I NEED TO DO:
SELECT * from tblMy WHERE ReceivedDate BETWEEN #StartDate AND #EndDate

Answer 1

If you fix your JSON to not use stylised double quotes (”) and use standard ones (") then you can parse this as JSON. Once you extract the values, you can inject a couple of / characters in and then convert to a date with the style code 103 (dd/MM/yyyy):
DECLARE #String nvarchar(MAX) = N'{ "date_from":"22112017","date_to":"22112017"}';
SELECT CONVERT(date,STUFF(STUFF(OJ.date_from,5,0,'/'),3,0,'/'),103) AS date_from,
CONVERT(date,STUFF(STUFF(OJ.date_to,5,0,'/'),3,0,'/'),103) AS date_to
FROM (VALUES(#String))V(S)
CROSS APPLY OPENJSON(V.S)
WITH (date_from varchar(8),
date_to varchar(8)) OJ;
Edit:
Seems the OP has moved their goal posts, this has nothing to do with JSON.
The problem here is your literal strings. When using literal strings for a date and time data type use either yyyyMMdd or yyyy-MM-ddThh:mm:ss.nnnnnnn as they are both unambiguous regardless of language and data type:
DECLARE #StartDate date,
#EndDate date;
SET #StartDate = '20171222';
SET #EndDAte = '20201122';
SELECT *
FROM tblMy
WHERE ReceivedDate BETWEEN #StartDate AND #EndDate;

Answer 2

I would suggest converting the value to a standard SQL Server date value. This is pretty simple:
select convert(date, left(val, 4) + substring(val, 3, 2) + right(val, 2))
The standard date format is YYYYMMDD. Yours is DDMMYYYY, so string operations can convert it to the correct format. Of course, what you should probably do is to convert the value to a date in the application layer and pass the date value in as a parameter.

Answer 3

This should fix the error "Error: Conversion failed when converting date and/or time from character string."
DECLARE #EndDate VARCHAR(MAX) = '22112017'
DECLARE #datevar date = CAST(SUBSTRING(#EndDate, 3, 2) + '/' + SUBSTRING(#EndDate,
1, 2) + '/' + SUBSTRING(#EndDate, 5, 4) AS date);
SELECT #datevar;