左连接上的模糊匹配

Question

I am looking to join two tables where there's a 90% match for example.

Taking the example below, I want to join table A and table B on the phone number. You can see that the phone numbers differ slightly (the international code). I'd like the end result to show as table C.

I imagine it'll be something like but the join would specify to match on 90% of the phone_number

select
a.*,
b.most_recent_booking_date
from a 
left join b
on a.phone_number = b.phone_number

Hope that's clear and any help would be great! Cheers!

Table A

Phone number	Most recent call date
441234567891	01/05/22
441234567892	02/05/22

Table B

Phone number	Most recent booking date
+441234567891	03/05/22
+441234567892	04/05/22

Table C

Phone number	Most recent call date	Most recent bookingdate
441234567891	01/05/22	03/05/22
441234567892	02/05/22	04/05/22

Answer 1

You can try something like this, but I don't like it, as Demeteor says you should have an ID to join on. Note that I use a left join here, in case there is no data in table #T2. I was also considering a computed column where it removes the + and then you could join that way too. I will also get told off for SQL injection if the phone number could be dodgy.

CREATE TABLE #T1 (
    PhoneNumber VARCHAR(20) NOT NULL, 
    CallDate DATE NOT NULL
);

CREATE TABLE #T2 (
    PhoneNumber VARCHAR(20) NOT NULL, 
    BookingDate DATE NOT NULL
);

INSERT INTO #T1 (PhoneNumber, CallDate)
VALUES
('441234567891', '20220501'),
('441234567892', '20220502');


INSERT INTO #T2 (PhoneNumber, BookingDate)
VALUES
('+441234567891', '20220503'),
('+441234567892', '20220504');

GO

SELECT *
FROM #T1 AS T1
LEFT JOIN #T2 AS T2 ON T2.PhoneNumber LIKE '%' + T1.PhoneNumber;