Select
Learn how to use the select method in tSQL.
Basic usage
const persons = await db
.selectFrom("person")
.select("id")
.where("first_name", "=", "Arnold")
.execute();Selecting multiple columns
const persons = await db
.selectFrom("person")
.select(["id", "first_name", "last_name"])
.execute();Selecting all columns
const persons = await db.selectFrom("person").selectAll().execute();Selecting with a custom alias
const persons = await db
.selectFrom("person as p")
.select(["first_name as fn", "p.last_name as ln"])
.execute();Complex selection
You can select arbitrary expression including subqueries and raw sql snippets. When you do that, you need to give a name for the selections using the as method:
import { sql } from "tsql";
const persons = await db
.selectFrom("person")
.select(({ eb, selectFrom, or }) => [
// Select a correlated subquery
selectFrom("pet")
.whereRef("person.id", "=", "pet.owner_id")
.select("pet.name")
.orderBy("pet.name")
.limit(1)
.as("first_pet_name"),
// Build and select an expression using
// the expression builder
or([eb("first_name", "=", "Jennifer"), eb("first_name", "=", "Arnold")]).as(
"is_jennifer_or_arnold"
),
// Select a raw sql expression
sql<string>`concat(first_name, ' ', last_name)`.as("full_name"),
])
.execute();