One update SQL query from three tables - sql

Question

I have three tables and I have to write one query to update table 1 row from table 3 and the only matching columns I have is in table 2.
Table 1 which has incorrect data:
Table 3 has the correct data:
I did try to write a query and execute it but it gives me an error saying there are too many rows too select which is true I do have many rows to correct but it still wouldn't correct. What do you think I should do. This is my query so far.
UPDATE Table1
SET Table1.Number = (SELECT Table3.Number
FROM Table2
FULL OUTER JOIN Table1 ON Table1.ID = Table2.ID
FULL OUTER JOIN Table3 ON Table3.Signin = Table2.Signin
WHERE (Table2.ID = Table1.ID)
AND (Table1.Number = 'xxx'))
WHERE (Tale1.Number = 'xxx')

Answer 1

In Where clause of JOIN query need to modify as multiple records are generating by inappropriate condition.Try to use Table3 components instead of using Table1 in joining query where clause.
UPDATE Table1
SET Table1.NUMBER = (SELECT table3.NUMBER FROM Table1 FULL OUTER JOIN Table2
ON Table1.ID = Table2.ID
FULL OUTER JOIN Table3
ON Table2.SIGNIN = Table3.SIGNIN
WHERE Table3.SIGNIN = 100) // This is the point where you need to modify your code
WHERE Table1.ID = 1;
ONLINE DEMO HERE

Answer 2

It actually worked after I removed this line from my query.
FULL OUTER JOIN Table1 ON table1.ID = Table2.ID
Thanks for the help.

Answer 3

You are fairly close. When doing the update though unless you are wanting to clear value for t1.number when a record is not matched in t3, you will want to use INNER JOIN. FULL OUTER JOIN would mean you are trying to update rows in t1 that don't exist but a LEFT JOIN you would update t1.number to NULL if a record in t3 doesn't exist.
UPDATE t1
SET t1.Number = t3.Number
FROM
Table1 t1
INNER JOIN Table2 t2
ON t1.Id = t2.Id
INNER JOIN Table3 t3
ON t2.Signin = t.3.Signin
WHERE
t1.number <> t3.number
--Or if you have nulls something like
--ISNULL(t1.number,'xxx') <> ISNULL(t3.number,'xxx')
-- if you only want to update when t1.number = 'xxx' then
--t1.number = 'xxx'
t1,t2,t3 are table aliases that I created by adding the alias after table name. By using join syntax rather than a sub select you simplify your were conditions. In sql-sever if more than 1 record in t2 & t3 match it will select one row randomly in the case of a one to many relationship. If you want a specific record when not one to one relation you can use window functions and common table expressions (cte) to limit t3 to the exact record you want to use.