update query result not reflecting in table - sql

Question

I have two tables test1 and test2. What I need is, I would like to update one column in the table test2 with data from the table test1. My query is
UPDATE test2 t2
SET t2.name = (SELECT t1.name
FROM test1 t1
WHERE t1.id = t2.mob)
WHERE t2.mob IN (SELECT t1.id
FROM test1 t1
WHERE t1.id = t2.mob)
It's showing 3 Rows updated , But It's not reflecting in my table. My reference. Is there any issue in my query. Or what should I do alternately.

Answer 1

It wold be easier to use merge statement:
/* test tables */
SQL> create table test1(id1, name1) as
2 select level
3 , dbms_random.string('l', 7)
4 from dual
5 connect by level <= 5;
Table created
SQL> create table test2(id1, name1) as
2 select level
3 , cast(null as varchar2(11))
4 from dual
5 connect by level <= 5;
Table created
Tables' contents:
SQL> column name1 format a10;
SQL> select * from test1;
ID1 NAME1
---------- ----------
1 ouegwac
2 bptytsz
3 xwpnuqi
4 jrbxeza
5 hlckwvk
SQL> select * from test2;
ID1 NAME1
---------- ----------
1 NULL
2 NULL
3 NULL
4 NULL
5 NULL
Update test2.name1 column with data from test1.name1 column:
SQL> merge into test2 t
2 using test1 q
3 on (q.id1 = t.id1)
4 when matched then
5 update set t.name1 = q.name1
6 ;
5 rows merged
SQL> select * from test2;
ID1 NAME1
---------- ----------
1 ouegwac
2 bptytsz
3 xwpnuqi
4 jrbxeza
5 hlckwvk

Answer 2

UPDATE
(SELECT test2.name as t2, test1.name as t1
FROM test2
INNER JOIN test1
ON test2.MOB= test1.ID
) t
SET t.t2= t.t1

Answer 3

The WHERE part in your query is absolutely unnecessary because it always evaluates to TRUE. So the correct one to update all rows in t2 is:
UPDATE test2 t2
SET t2.name = (SELECT t1.name
FROM test1 t1
WHERE t1.id = t2.mob)
Also in PL/SQL Developer transactions are not commited automatically by default. You have to manually commit it by pressing that green arrow on the panel.