Oracle 23c

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-- temporary table to mimic your query
create table t (rn, quantity) as
select 1, rownum from dual connect by level <= 5 union all
select 2, rownum from dual connect by level <= 7 union all
select 3, rownum from dual connect by level <= 3
15 rows affected

-- showing these are numeric literals not column references
select 1 as x1, 2 as x2, 3 as x3
from dual


X1
X2
X3


1
2
3


-- replicating your result
select 1 as x1, 2 as x2, 3 as x3
from t
pivot (sum(quantity) for rn in (1, 2, 3))


X1
X2
X3


1
2
3


-- with quoted identifiers
select "1", "2", "3"
from t
pivot (sum(quantity) for rn in (1, 2, 3))


1
2
3


15
28
6


-- with sum alias
select "1_QTY", "2_QTY", "3_QTY"
from t
pivot (sum(quantity) as qty for rn in (1, 2, 3))


1_QTY
2_QTY
3_QTY


15
28
6


-- with value aliases
select q1, q2, q3
from t
pivot (sum(quantity) for rn in (1 as q1, 2 as q2, 3 as q3))


Q1
Q2
Q3


15
28
6


-- with both aliases
select q1_qty, q2_qty, q3_qty
from t
pivot (sum(quantity) as qty for rn in (1 as q1, 2 as q2, 3 as q3))


Q1_QTY
Q2_QTY
Q3_QTY


15
28
6