diff --git a/sqlx-core/src/any/mod.rs b/sqlx-core/src/any/mod.rs
index f3f548e0..a5cd03e4 100644
--- a/sqlx-core/src/any/mod.rs
+++ b/sqlx-core/src/any/mod.rs
@@ -35,7 +35,7 @@ pub type AnyPool = crate::pool::Pool<Any>;
 impl_into_arguments_for_arguments!(AnyArguments<'q>);
 impl_executor_for_pool_connection!(Any, AnyConnection, AnyRow);
 impl_executor_for_transaction!(Any, AnyRow);
+impl_map_row!(Any, AnyRow);
 
-// required because some databases have a different handling
-// of NULL
+// required because some databases have a different handling of NULL
 impl_encode_for_option!(Any);
diff --git a/sqlx-core/src/lib.rs b/sqlx-core/src/lib.rs
index 5db5b076..efbb69e4 100644
--- a/sqlx-core/src/lib.rs
+++ b/sqlx-core/src/lib.rs
@@ -43,6 +43,9 @@ pub mod decode;
 #[macro_use]
 pub mod types;
 
+#[macro_use]
+pub mod query;
+
 mod common;
 pub mod database;
 pub mod describe;
@@ -50,7 +53,6 @@ pub mod executor;
 pub mod from_row;
 mod io;
 mod net;
-pub mod query;
 pub mod query_as;
 pub mod query_scalar;
 pub mod row;
diff --git a/sqlx-core/src/mssql/mod.rs b/sqlx-core/src/mssql/mod.rs
index 9708f229..22cc58de 100644
--- a/sqlx-core/src/mssql/mod.rs
+++ b/sqlx-core/src/mssql/mod.rs
@@ -30,6 +30,4 @@ pub type MssqlPool = crate::pool::Pool<Mssql>;
 impl_into_arguments_for_arguments!(MssqlArguments);
 impl_executor_for_pool_connection!(Mssql, MssqlConnection, MssqlRow);
 impl_executor_for_transaction!(Mssql, MssqlRow);
-
-// FIXME: RPC NULL parameter values / results
-// FIXME: RPC Empty String parameter values
+impl_map_row!(Mssql, MssqlRow);
diff --git a/sqlx-core/src/mysql/mod.rs b/sqlx-core/src/mysql/mod.rs
index 64a5bbba..aca0cf22 100644
--- a/sqlx-core/src/mysql/mod.rs
+++ b/sqlx-core/src/mysql/mod.rs
@@ -30,7 +30,7 @@ pub type MySqlPool = crate::pool::Pool<MySql>;
 impl_into_arguments_for_arguments!(MySqlArguments);
 impl_executor_for_pool_connection!(MySql, MySqlConnection, MySqlRow);
 impl_executor_for_transaction!(MySql, MySqlRow);
+impl_map_row!(MySql, MySqlRow);
 
-// required because some databases have a different handling
-// of NULL
+// required because some databases have a different handling of NULL
 impl_encode_for_option!(MySql);
diff --git a/sqlx-core/src/postgres/mod.rs b/sqlx-core/src/postgres/mod.rs
index c49cc7a6..60c335a4 100644
--- a/sqlx-core/src/postgres/mod.rs
+++ b/sqlx-core/src/postgres/mod.rs
@@ -33,7 +33,7 @@ pub type PgPool = crate::pool::Pool<Postgres>;
 impl_into_arguments_for_arguments!(PgArguments);
 impl_executor_for_pool_connection!(Postgres, PgConnection, PgRow);
 impl_executor_for_transaction!(Postgres, PgRow);
+impl_map_row!(Postgres, PgRow);
 
-// required because some databases have a different handling
-// of NULL
+// required because some databases have a different handling of NULL
 impl_encode_for_option!(Postgres);
diff --git a/sqlx-core/src/query.rs b/sqlx-core/src/query.rs
index 84e4f29c..61dec8cd 100644
--- a/sqlx-core/src/query.rs
+++ b/sqlx-core/src/query.rs
@@ -302,6 +302,40 @@ where
     }
 }
 
+// A (hopefully) temporary workaround for an internal compiler error (ICE) involving higher-ranked
+// trait bounds (HRTBs), associated types and closures.
+//
+// See https://github.com/rust-lang/rust/issues/62529
+
+pub trait TryMapRow<DB: Database> {
+    type Output: Unpin;
+
+    fn try_map_row(&mut self, row: DB::Row) -> Result<Self::Output, Error>;
+}
+
+pub trait MapRow<DB: Database> {
+    type Output: Unpin;
+
+    fn map_row(&mut self, row: DB::Row) -> Self::Output;
+}
+
+// A private adapter that implements [MapRow] in terms of [TryMapRow]
+// Just ends up Ok wrapping it
+
+struct MapRowAdapter<F>(F);
+
+impl<DB: Database, O, F> TryMapRow<DB> for MapRowAdapter<F>
+where
+    O: Unpin,
+    F: MapRow<DB, Output = O>,
+{
+    type Output = O;
+
+    fn try_map_row(&mut self, row: DB::Row) -> Result<Self::Output, Error> {
+        Ok(self.0.map_row(row))
+    }
+}
+
 /// Make a SQL query.
 #[inline]
 pub fn query<DB>(sql: &str) -> Query<'_, DB, <DB as HasArguments<'_>>::Arguments>
@@ -328,3 +362,30 @@ where
         query: sql,
     }
 }
+
+#[allow(unused_macros)]
+macro_rules! impl_map_row {
+    ($DB:ident, $R:ident) => {
+        impl<O: Unpin, F> crate::query::MapRow<$DB> for F
+        where
+            F: FnMut($R) -> O,
+        {
+            type Output = O;
+
+            fn map_row(&mut self, row: $R) -> O {
+                (self)(row)
+            }
+        }
+
+        impl<O: Unpin, F> crate::query::TryMapRow<$DB> for F
+        where
+            F: FnMut($R) -> Result<O, crate::error::Error>,
+        {
+            type Output = O;
+
+            fn try_map_row(&mut self, row: $R) -> Result<O, crate::error::Error> {
+                (self)(row)
+            }
+        }
+    };
+}
diff --git a/sqlx-core/src/sqlite/mod.rs b/sqlx-core/src/sqlite/mod.rs
index bb25f45f..ff891dc8 100644
--- a/sqlx-core/src/sqlite/mod.rs
+++ b/sqlx-core/src/sqlite/mod.rs
@@ -34,7 +34,7 @@ pub type SqlitePool = crate::pool::Pool<Sqlite>;
 impl_into_arguments_for_arguments!(SqliteArguments<'q>);
 impl_executor_for_pool_connection!(Sqlite, SqliteConnection, SqliteRow);
 impl_executor_for_transaction!(Sqlite, SqliteRow);
+impl_map_row!(Sqlite, SqliteRow);
 
-// required because some databases have a different handling
-// of NULL
+// required because some databases have a different handling of NULL
 impl_encode_for_option!(Sqlite);
diff --git a/src/lib.rs b/src/lib.rs
index 5d9d9b52..5c9803be 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -113,6 +113,7 @@ pub mod decode {
 /// Return types for the `query` family of functions and macros.
 pub mod query {
     pub use sqlx_core::query::{Map, Query};
+    pub use sqlx_core::query::{MapRow, TryMapRow};
     pub use sqlx_core::query_as::QueryAs;
     pub use sqlx_core::query_scalar::QueryScalar;
 }
diff --git a/tests/sqlite/sqlite.db b/tests/sqlite/sqlite.db
index fa00c6fb..77339064 100644
Binary files a/tests/sqlite/sqlite.db and b/tests/sqlite/sqlite.db differ