Select only part of fields

[YoshieraHuang]

Hi guys, can sea-orm select only part of fields in Model rather than the whole Model?

[billy1624]

Hi @YoshieraHuang, yes you can!

// Selecting the name column only
assert_eq!(
    cake::Entity::find()
        .select_only()
        .column(cake::Column::Name)
        .build(DbBackend::Postgres)
        .to_string(),
    r#"SELECT "cake"."name" FROM "cake""#
);

And, you can derive FromQueryResult if want to select partial fields into custom struct.

sea-orm/tests/relational_tests.rs

Lines 663 to 689 in 6a0db92

	#[derive(Debug, FromQueryResult, PartialEq)]
	struct BakerLite {
	name: String,
	}
	#[derive(Debug, FromQueryResult, PartialEq)]
	struct CustomerLite {
	name: String,
	}
	let baked_for_customers: Vec<(BakerLite, Option<CustomerLite>)> = Baker::find()
	.find_also_linked(baker::BakedForCustomer)
	.select_only()
	.column_as(baker::Column::Name, (SelectA, baker::Column::Name))
	.column_as(
	Expr::tbl(Alias::new("r4"), customer::Column::Name).into_simple_expr(),
	(SelectB, customer::Column::Name),
	)
	.group_by(baker::Column::Id)
	.group_by(Expr::tbl(Alias::new("r4"), customer::Column::Id).into_simple_expr())
	.group_by(baker::Column::Name)
	.group_by(Expr::tbl(Alias::new("r4"), customer::Column::Name).into_simple_expr())
	.order_by_asc(baker::Column::Id)
	.order_by_asc(Expr::tbl(Alias::new("r4"), customer::Column::Id).into_simple_expr())
	.into_model()
	.all(&ctx.db)
	.await?;

[YoshieraHuang]

Uhh @billy1624 , I find this at Advanced Queries/Custom Select in docs later. Thank you for your kind reply.