How to fix an error when using Alias in Oracle - sql

Question

I am receiving a syntax error when running the following code
42601: syntax error at or near "."
I think it has something to do with the alias but I cannot see where the problem is.
SELECT * FROM (
SELECT
m.shipment_id
m.route_id,
m.leg_sequence_id,
m.leg_warehouse_id,
m.leg_ship_method,
row_number() over (partition by m.route_id order by m.leg_sequence_id desc) as rn
FROM posimorders.sc_execution_eu.o_detailed_routes_v2 m
)
WHERE rn=1
LIMIT 100;

Answer 1

Your code includes:
SELECT * FROM (
SELECT
m.shipment_id
m.route_id,
...
You are missing a comma after m.shipment_id so it is trying to interpret m.route_id as a column alias for the shipment ID, which isn't what you intended; and an alias is a single identifier rather than a dot-separated hierarchy. Hence the error you are seeing, though that isn't coming from Oracle itself - your client seems to be parsing it first.
Oracle also doesn't support LIMIT, but from 12c it has a row-limiting clause you can use instead:
SELECT * FROM (
SELECT
m.shipment_id,
m.route_id,
m.leg_sequence_id,
m.leg_warehouse_id,
m.leg_ship_method,
row_number() over (partition by m.route_id order by m.leg_sequence_id desc) as rn
FROM posimorders.sc_execution_eu.o_detailed_routes_v2 m
)
WHERE rn=1
FETCH FIRST 100 ROWS ONLY;
or WITH TIES if you prefer.
The three levels in posimorders.sc_execution_eu.o_detailed_routes_v2 looks wrong too though... see the docs.