Query with “Logical operator (AND)” that does not return the desired result set

Question

I have a table:

create table test_table
(customer_num  NUMBER,
 dep_group     VARCHAR2(50),
 dep_type      VARCHAR2(50),
 balance       NUMBER)

the table has two records:

                  " test_table "
 --------------------------------------------------  
 customer_num   dep_group   dep_type    balance       
     1            x           x1          10
     1            x           x2          10

The query below must return two records of the table but it does not, and it's weird!!

select *
from test_table
where ((dep_group = 'x') AND (dep_type = 'x1') AND ((balance) > 1)
   
           AND
   
     ((dep_group = 'x') AND (dep_type = 'x2') AND ((balance) > 1)))

when I run each part of the query separately , it gives me the desired record

Q1:
 select *
 from test_tablet t
 where (dep_group = 'x') AND (dep_type = 'x1') AND ((balance) > 1) 

Q2:
 select *
 from test_tablet t
 where (dep_group = 'x') AND (dep_type = 'x2') AND ((balance) > 1) 

I mean customer = 1 matches both conditions and the original query must give me the two records of the table. Is there something wrong with my query or my understanding of the logical operators?

Thanks in advance.

Answer 1

As Mustaccio mentioned in the comments, you want rows where dev_type is either 'x1' or 'x2', not where it's 'x1' and 'x2'.

Also you only need the brackets around each of the alternative sets of conditions. The others aren't doing anything and they are just confusing.

with test_table (customer_num, dep_group, dep_type, balance) as
     ( select 1, 'x', 'x1', 10 from dual union all
       select 1, 'x', 'x2', 10 from dual
     )
select *
from  test_table
where (dep_group = 'x' and dep_type = 'x1' and balance > 1)
or    (dep_group = 'x' and dep_type = 'x2' and balance > 1)