ORDER BY

By default the rows come back in whatever order the table happens to hold them. ORDER BY sorts them by a column before they reach you.

name             station  price
Bifteki          grill    18
Baklava          pastry   7
Melitzanosalata  salad    16
Loukoumades      pastry   9
Souvlaki         grill    11
Dakos            salad    14

It goes on the very end, after WHERE if you have one. ORDER BY price sorts smallest to largest, which is what you get unless you say otherwise.

SELECT name, price
FROM dishes
ORDER BY price;

name             price
Baklava          7
Loukoumades      9
Souvlaki         11
Dakos            14
Melitzanosalata  16
Bifteki          18

Add DESC to flip it and go largest to smallest. ASC is the default, and spells out ascending if you ever want to be explicit.

SELECT name, price
FROM dishes
ORDER BY price DESC;

name             price
Bifteki          18
Melitzanosalata  16
Dakos            14
Souvlaki         11
Loukoumades      9
Baklava          7

It sorts text too, running A to Z.

SELECT name
FROM dishes
ORDER BY name;

name
Baklava
Bifteki
Dakos
Loukoumades
Melitzanosalata
Souvlaki

You can also sort by more than one column. List them separated by commas and SQL sorts by the first one, then uses the next to break any ties. This groups every dish by station, and puts the cheapest first inside each group.

SELECT name, station, price
FROM dishes
ORDER BY station, price;

name             station  price
Souvlaki         grill    11
Bifteki          grill    18
Baklava          pastry   7
Loukoumades      pastry   9
Dakos            salad    14
Melitzanosalata  salad    16

You can flip each column on its own, too: ORDER BY station, price DESC keeps the stations in A to Z order but lists the priciest dish first inside each one.

ORDER BY only changes the order of the rows, never which rows or columns you get. With SELECT, WHERE and ORDER BY you can already answer most of what the rail throws at you.