如何更新postgres中其他表的值

Question

currently I have 3 tables

Table 1:

tb1_id	values
1	4

Table 2:

tb1_id	tbl3_id
1	5

Table 3:

tb3_id	values
5	2

For some reason the values from table 1 are not the same in table 3 (as shown above), I need to update the values of the table 1 with the table 3, but I am not able to do so, so far this is my query:

UPDATE
    table1 t1
SET 
    values =  temp_tbl.values
FROM 
    (
        SELECT t2.tb1_id, t3.values FROM table2 t2
        JOIN 
        table3 t3 ON t2.tbl3_id = t3.tbl3_id
    ) temp_tbl
WHERE 
      t1.tbl1_id = temp_tbl.tbl1_id
AND
    t1.values != temp_tbl.values;

Answer 1

this is how you can do it:

-- temporary tables

SELECT 1 TBL1_ID, 4 valuet1 INTO #t1

SELECT 1 TBL1_ID, 5 TBL3_Id INTO #t2

SELECT 5 TBL3_ID, 2 valuet3 INTO #t3

Blockquote

-- select with joins

select T1. ,T2. , T3.* from #t1 T1 INNER JOIN #t2 T2 ON T1.TBL1_ID = T2.TBL1_ID INNER JOIN #t3 T3 ON T3.TBL3_ID = T2.TBL3_ID

-- update would be like this

update #t1 set valuet1 = T3.valuet3 from #t1 T1 INNER JOIN #t2 T2 ON T1.TBL1_ID = T2.TBL1_ID INNER JOIN #t3 T3 ON T3.TBL3_ID = T2.TBL3_ID

Answer 2

OK so if I understood you correctly, you just need to make a slight correction to your code:

UPDATE
    table1 t1
SET 
    values =  temp_tbl.values
FROM 
    (
        SELECT t2.tbl1_id, t3.values 
        FROM table2 t2
        Inner JOIN table3 t3 ON t2.tbl3_id = t3.tbl3_id
    ) temp_tbl
WHERE 
      t1.tbl1_id = temp_tbl.tbl1_id
AND
    t1.values != temp_tbl.values;

Here is DBFiddle link.

EDIT: This would also do:

with newData as (
   select t1.tbl1_id, t3.Values
   from Table1 t1
   inner join Table2 t2 on t1.Tbl1_Id = t2.Tbl1_Id
   inner join Table3 t3 on t2.Tbl3_Id = t3.Tbl3_Id
   where t1.Values != t3.Values
)
UPDATE
    table1
SET 
    values = newData.Values
FROM newData 
where table1.tbl1_id = newData.tbl1_id;