Here's the example:
ID | value
1 51
2 25
3 11
4 27
5 21
I need to get first three parameters and place them into variables eg out_x, out_y, out_z. Is it possible to do it without multiple selects?
You can do something like this:
select max(case when id = 1 then value end),
max(case when id = 2 then value end),
max(case when id = 3 then value end)
into out_x, out_y, out_z
from t
where id in (1, 2, 3);
However, I think three queries of the form:
select value into out_x
from t
where id = 1;
is a cleaner approach.
You can use a PIVOT
:
SELECT x, y, z
INTO out_x, out_y, out_z
FROM your_table
PIVOT ( MAX( value ) FOR id IN ( 1 AS x, 2 AS y, 3 AS z ) )
Or, if you do not know which ID
s you need (but just want the first 3) then:
SELECT x, y, z
INTO out_x, out_y, out_z
FROM (
SELECT value, ROWNUM AS rn
FROM ( SELECT value FROM your_table ORDER BY id )
WHERE ROWNUM <= 3
)
PIVOT ( MAX( value ) FOR rn IN ( 1 AS x, 2 AS y, 3 AS z ) )
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