Update query helper column_as

src/entity/identity.rs

@@ -1,5 +1,6 @@
 use crate::{ColumnTrait, EntityTrait, IdenStatic};
-use sea_query::{DynIden, IntoIden};
+use sea_query::{Alias, DynIden, Iden, IntoIden, SeaRc};
+use std::fmt;
 
 #[derive(Debug, Clone)]
 pub enum Identity {
@@ -8,6 +9,25 @@ pub enum Identity {
     Ternary(DynIden, DynIden, DynIden),
 }
 
+impl Iden for Identity {
+    fn unquoted(&self, s: &mut dyn fmt::Write) {
+        match self {
+            Identity::Unary(iden) => {
+                write!(s, "{}", iden.to_string()).unwrap();
+            }
+            Identity::Binary(iden1, iden2) => {
+                write!(s, "{}", iden1.to_string()).unwrap();
+                write!(s, "{}", iden2.to_string()).unwrap();
+            }
+            Identity::Ternary(iden1, iden2, iden3) => {
+                write!(s, "{}", iden1.to_string()).unwrap();
+                write!(s, "{}", iden2.to_string()).unwrap();
+                write!(s, "{}", iden3.to_string()).unwrap();
+            }
+        }
+    }
+}
+
 pub trait IntoIdentity {
     fn into_identity(self) -> Identity;
 }
@@ -19,6 +39,18 @@ where
     fn identity_of(self) -> Identity;
 }
 
+impl IntoIdentity for String {
+    fn into_identity(self) -> Identity {
+        self.as_str().into_identity()
+    }
+}
+
+impl IntoIdentity for &str {
+    fn into_identity(self) -> Identity {
+        Identity::Unary(SeaRc::new(Alias::new(self)))
+    }
+}
+
 impl<T> IntoIdentity for T
 where
     T: IdenStatic,

src/executor/select.rs

@@ -1,6 +1,6 @@
 use crate::{
-    error::*, query::combine, DatabaseConnection, EntityTrait, FromQueryResult, Iterable,
-    JsonValue, ModelTrait, Paginator, PrimaryKeyToColumn, QueryResult, Select, SelectTwo,
+    error::*, DatabaseConnection, EntityTrait, FromQueryResult, IdenStatic, Iterable, JsonValue,
+    ModelTrait, Paginator, PrimaryKeyToColumn, QueryResult, Select, SelectA, SelectB, SelectTwo,
     SelectTwoMany, Statement,
 };
 use sea_query::SelectStatement;
@@ -66,8 +66,8 @@ where
 
     fn from_raw_query_result(res: QueryResult) -> Result<Self::Item, DbErr> {
         Ok((
-            M::from_query_result(&res, combine::SELECT_A)?,
-            N::from_query_result_optional(&res, combine::SELECT_B)?,
+            M::from_query_result(&res, SelectA.as_str())?,
+            N::from_query_result_optional(&res, SelectB.as_str())?,
         ))
     }
 }

src/query/combine.rs

@@ -1,10 +1,31 @@
-use crate::{EntityTrait, IntoSimpleExpr, Iterable, QueryTrait, Select, SelectTwo, SelectTwoMany};
+use crate::{
+    EntityTrait, IdenStatic, IntoSimpleExpr, Iterable, QueryTrait, Select, SelectTwo, SelectTwoMany,
+};
 use core::marker::PhantomData;
 pub use sea_query::JoinType;
 use sea_query::{Alias, ColumnRef, Iden, Order, SeaRc, SelectExpr, SelectStatement, SimpleExpr};
 
-pub const SELECT_A: &str = "A_";
-pub const SELECT_B: &str = "B_";
+macro_rules! select_def {
+    ( $ident: ident, $str: expr ) => {
+        #[derive(Debug, Clone, Copy)]
+        pub struct $ident;
+
+        impl Iden for $ident {
+            fn unquoted(&self, s: &mut dyn std::fmt::Write) {
+                write!(s, "{}", self.as_str()).unwrap();
+            }
+        }
+
+        impl IdenStatic for $ident {
+            fn as_str(&self) -> &str {
+                $str
+            }
+        }
+    };
+}
+
+select_def!(SelectA, "A_");
+select_def!(SelectB, "B_");
 
 impl<E> Select<E>
 where
@@ -37,7 +58,7 @@ where
     where
         F: EntityTrait,
     {
-        self = self.apply_alias(SELECT_A);
+        self = self.apply_alias(SelectA.as_str());
         SelectTwo::new(self.into_query())
     }
 
@@ -45,7 +66,7 @@ where
     where
         F: EntityTrait,
     {
-        self = self.apply_alias(SELECT_A);
+        self = self.apply_alias(SelectA.as_str());
         SelectTwoMany::new(self.into_query())
     }
 }
@@ -102,7 +123,7 @@ where
     S: QueryTrait<QueryStatement = SelectStatement>,
 {
     for col in <F::Column as Iterable>::iter() {
-        let alias = format!("{}{}", SELECT_B, col.to_string().as_str());
+        let alias = format!("{}{}", SelectB.as_str(), col.as_str());
         selector.query().expr(SelectExpr {
             expr: col.into_simple_expr(),
             alias: Some(SeaRc::new(Alias::new(&alias))),

src/query/helper.rs

@@ -1,11 +1,9 @@
 use crate::{
-    ColumnTrait, EntityTrait, Identity, IntoSimpleExpr, Iterable, ModelTrait, PrimaryKeyToColumn,
-    RelationDef,
-};
-use sea_query::{
-    Alias, Expr, Iden, IntoCondition, SeaRc, SelectExpr, SelectStatement, SimpleExpr, TableRef,
+    ColumnTrait, EntityTrait, Identity, IntoIdentity, IntoSimpleExpr, Iterable, ModelTrait,
+    PrimaryKeyToColumn, RelationDef,
 };
 pub use sea_query::{Condition, ConditionalStatement, DynIden, JoinType, Order, OrderedStatement};
+use sea_query::{Expr, IntoCondition, SeaRc, SelectExpr, SelectStatement, SimpleExpr, TableRef};
 
 // LINT: when the column does not appear in tables selected from
 // LINT: when there is a group by clause, but some columns don't have aggregate functions
@@ -55,40 +53,14 @@ pub trait QuerySelect: Sized {
     ///     r#"SELECT COUNT("cake"."id") AS "count" FROM "cake""#
     /// );
     /// ```
-    fn column_as<C>(mut self, col: C, alias: &str) -> Self
+    fn column_as<C, I>(mut self, col: C, alias: I) -> Self
     where
         C: IntoSimpleExpr,
+        I: IntoIdentity,
     {
         self.query().expr(SelectExpr {
             expr: col.into_simple_expr(),
-            alias: Some(SeaRc::new(Alias::new(alias))),
-        });
-        self
-    }
-
-    /// Add a select column with prefixed alias
-    /// ```
-    /// use sea_orm::{entity::*, query::*, tests_cfg::cake, DbBackend};
-    ///
-    /// assert_eq!(
-    ///     cake::Entity::find()
-    ///         .select_only()
-    ///         .column_as_prefixed(cake::Column::Id.count(), "A_", cake::Column::Id)
-    ///         .build(DbBackend::Postgres)
-    ///         .to_string(),
-    ///     r#"SELECT COUNT("cake"."id") AS "A_id" FROM "cake""#
-    /// );
-    /// ```
-    fn column_as_prefixed<C, I>(mut self, col: C, prefix: &str, alias: I) -> Self
-    where
-        C: IntoSimpleExpr,
-        I: Iden,
-    {
-        self.query().expr(SelectExpr {
-            expr: col.into_simple_expr(),
-            alias: Some(SeaRc::new(Alias::new(
-                vec![prefix, alias.to_string().as_str()].join("").as_str(),
-            ))),
+            alias: Some(SeaRc::new(alias.into_identity())),
         });
         self
     }

src/query/mod.rs

@@ -9,7 +9,7 @@ mod select;
 mod traits;
 mod update;
 
-// pub use combine::*;
+pub use combine::{SelectA, SelectB};
 pub use delete::*;
 pub use helper::*;
 pub use insert::*;

tests/relational_tests.rs

@@ -484,6 +484,7 @@ pub async fn having() {
 ))]
 pub async fn linked() -> Result<(), DbErr> {
     use common::bakery_chain::Order;
+    use sea_orm::{SelectA, SelectB};
 
     let ctx = TestContext::new("test_linked").await;
 
@@ -665,8 +666,8 @@ pub async fn linked() -> Result<(), DbErr> {
     let baked_for_customers: Vec<(BakerLite, Option<CustomerLite>)> = Baker::find()
         .find_also_linked(baker::BakedForCustomer)
         .select_only()
-        .column_as_prefixed(baker::Column::Name, "A_", baker::Column::Name)
-        .column_as_prefixed(customer::Column::Name, "B_", customer::Column::Name)
+        .column_as(baker::Column::Name, (SelectA, baker::Column::Name))
+        .column_as(customer::Column::Name, (SelectB, customer::Column::Name))
         .group_by(baker::Column::Id)
         .group_by(customer::Column::Id)
         .group_by(baker::Column::Name)