Generic min max (pointfreeco#76)

* updated to QueryValue so for example we can return a date in an @selection

* removed foundation import

* used the optionalised functions from optional-helpers

* wip

---------

Co-authored-by: Stephen Celis <[email protected]>

Author: Graveion

Sources/StructuredQueriesCore/AggregateFunctions.swift

@@ -84,7 +84,7 @@ where QueryValue: _OptionalPromotable, QueryValue._Optionalized.Wrapped == Strin
   }
 }
 
-extension QueryExpression where QueryValue: QueryBindable {
+extension QueryExpression where QueryValue: QueryBindable & _OptionalPromotable {
   /// A maximum aggregate of this expression.
   ///
   /// ```swift
@@ -96,10 +96,11 @@ extension QueryExpression where QueryValue: QueryBindable {
   /// - Returns: A maximum aggregate of this expression.
   public func max(
     filter: (some QueryExpression<Bool>)? = Bool?.none
-  ) -> some QueryExpression<Int?> {
+  ) -> some QueryExpression<QueryValue._Optionalized.Wrapped?> {
     AggregateFunction("max", [queryFragment], filter: filter?.queryFragment)
   }
 
+
   /// A minimum aggregate of this expression.
   ///
   /// ```swift
@@ -111,7 +112,7 @@ extension QueryExpression where QueryValue: QueryBindable {
   /// - Returns: A minimum aggregate of this expression.
   public func min(
     filter: (some QueryExpression<Bool>)? = Bool?.none
-  ) -> some QueryExpression<Int?> {
+  ) -> some QueryExpression<QueryValue._Optionalized.Wrapped?> {
     AggregateFunction("min", [queryFragment], filter: filter?.queryFragment)
   }
 }
@@ -170,7 +171,7 @@ where QueryValue: _OptionalPromotable, QueryValue._Optionalized.Wrapped: Numeric
   ///
   /// ```swift
   /// Item.select { $0.price.total() }
-  /// // SELECT sum("items"."price") FROM "items"
+  /// // SELECT total("items"."price") FROM "items"
   /// ```
   ///
   /// - Parameters:

Tests/StructuredQueriesTests/AggregateFunctionsTests.swift

@@ -13,6 +13,7 @@ extension SnapshotTests {
       var name: String
       var isAdmin: Bool
       var age: Int?
+      var birthDate: Date?
     }
 
     @Test func average() {
@@ -93,45 +94,45 @@ extension SnapshotTests {
       }
     }
 
-    @Test func max() {
-      assertInlineSnapshot(of: User.columns.id.max(), as: .sql) {
-        """
-        max("users"."id")
-        """
-      }
-      assertQuery(Reminder.select { $0.id.max() }) {
-        """
-        SELECT max("reminders"."id")
-        FROM "reminders"
-        """
-      } results: {
-        """
-        ┌────┐
-        │ 10 │
-        └────┘
-        """
-      }
-    }
-
-    @Test func min() {
-      assertInlineSnapshot(of: User.columns.id.min(), as: .sql) {
-        """
-        min("users"."id")
-        """
-      }
-      assertQuery(Reminder.select { $0.priority.min() }) {
-        """
-        SELECT min("reminders"."priority")
-        FROM "reminders"
-        """
-      } results: {
-        """
-        ┌───┐
-        │ 1 │
-        └───┘
-        """
-      }
-    }
+	@Test func max() {
+	  assertInlineSnapshot(of: User.columns.birthDate.max(), as: .sql) {
+	    """
+	    max("users"."birthDate")
+	    """
+	  }
+	  assertQuery(Reminder.select { $0.dueDate.max() }) {
+	    """
+	    SELECT max("reminders"."dueDate")
+	    FROM "reminders"
+	    """
+	  }results: {
+	    """
+	    ┌────────────────────────────────┐
+	    │ Date(2001-01-05T00:00:00.000Z) │
+	    └────────────────────────────────┘
+	    """
+	  }
+	}
+	  
+	@Test func min() {
+	  assertInlineSnapshot(of: User.columns.birthDate.min(), as: .sql) {
+	    """
+	    min("users"."birthDate")
+	    """
+	 }
+	 assertQuery(Reminder.select { $0.dueDate.min() }) {
+	   """
+	   SELECT min("reminders"."dueDate")
+	   FROM "reminders"
+	   """
+	 } results: {
+	   """
+	   ┌────────────────────────────────┐
+	   │ Date(2000-06-25T00:00:00.000Z) │
+	   └────────────────────────────────┘
+	   """
+	  }
+	}
 
     @Test func sum() {
       assertInlineSnapshot(of: User.columns.id.sum(), as: .sql) {

Tests/StructuredQueriesTests/SelectTests.swift

@@ -1312,17 +1312,17 @@ extension SnapshotTests {
         }
       }
       do {
-        let query: some Statement<Int?> = Reminder.select { $0.priority.flatMap { $0.max() } }
+        let query: some Statement<Priority?> = Reminder.select { $0.priority.flatMap { $0.max() } }
         assertQuery(query) {
           """
           SELECT max("reminders"."priority")
           FROM "reminders"
           """
         } results: {
           """
-          ┌───┐
-          │ 3 │
-          └───┘
+          ┌───────┐
+          │ .high │
+          └───────┘
           """
         }
       }