diff --git a/sqlx-core/src/mssql/arguments.rs b/sqlx-core/src/mssql/arguments.rs
index af5d0adbc..f4ed37e8b 100644
--- a/sqlx-core/src/mssql/arguments.rs
+++ b/sqlx-core/src/mssql/arguments.rs
@@ -58,18 +58,10 @@ impl MssqlArguments {
         self.ordinal += arguments.ordinal;
         self.data.append(&mut arguments.data);
     }
-}
 
-impl<'q> Arguments<'q> for MssqlArguments {
-    type Database = Mssql;
-
-    fn reserve(&mut self, _additional: usize, size: usize) {
-        self.data.reserve(size + 10); // est. 4 chars for name, 1 for status, 1 for TYPE_INFO
-    }
-
-    fn add<T>(&mut self, value: T)
+    pub(crate) fn add<'q, T>(&mut self, value: T)
     where
-        T: 'q + Encode<'q, Self::Database> + Type<Mssql>,
+        T: Encode<'q, Mssql> + Type<Mssql>,
     {
         let ty = value.produces().unwrap_or_else(T::type_info);
 
@@ -109,3 +101,18 @@ impl<'q> Arguments<'q> for MssqlArguments {
         ty.0.put_value(data, value); // [ParamLenData]
     }
 }
+
+impl<'q> Arguments<'q> for MssqlArguments {
+    type Database = Mssql;
+
+    fn reserve(&mut self, _additional: usize, size: usize) {
+        self.data.reserve(size + 10); // est. 4 chars for name, 1 for status, 1 for TYPE_INFO
+    }
+
+    fn add<T>(&mut self, value: T)
+    where
+        T: 'q + Encode<'q, Self::Database> + Type<Mssql>,
+    {
+        self.add(value)
+    }
+}
diff --git a/sqlx-core/src/mysql/arguments.rs b/sqlx-core/src/mysql/arguments.rs
index 94a30f163..4a04561f2 100644
--- a/sqlx-core/src/mysql/arguments.rs
+++ b/sqlx-core/src/mysql/arguments.rs
@@ -1,5 +1,3 @@
-use std::ops::{Deref, DerefMut};
-
 use crate::arguments::Arguments;
 use crate::encode::{Encode, IsNull};
 use crate::mysql::{MySql, MySqlTypeInfo};
@@ -13,6 +11,23 @@ pub struct MySqlArguments {
     pub(crate) null_bitmap: Vec<u8>,
 }
 
+impl MySqlArguments {
+    pub(crate) fn add<'q, T>(&mut self, value: T)
+    where
+        T: Encode<'q, MySql> + Type<MySql>,
+    {
+        let ty = value.produces().unwrap_or_else(T::type_info);
+        let index = self.types.len();
+
+        self.types.push(ty);
+        self.null_bitmap.resize((index / 8) + 1, 0);
+
+        if let IsNull::Yes = value.encode(&mut self.values) {
+            self.null_bitmap[index / 8] |= (1 << (index % 8)) as u8;
+        }
+    }
+}
+
 impl<'q> Arguments<'q> for MySqlArguments {
     type Database = MySql;
 
@@ -25,28 +40,6 @@ impl<'q> Arguments<'q> for MySqlArguments {
     where
         T: Encode<'q, Self::Database> + Type<Self::Database>,
     {
-        let ty = value.produces().unwrap_or_else(T::type_info);
-        let index = self.types.len();
-
-        self.types.push(ty);
-        self.null_bitmap.resize((index / 8) + 1, 0);
-
-        if let IsNull::Yes = value.encode(self) {
-            self.null_bitmap[index / 8] |= (1 << (index % 8)) as u8;
-        }
-    }
-}
-
-impl Deref for MySqlArguments {
-    type Target = Vec<u8>;
-
-    fn deref(&self) -> &Self::Target {
-        &self.values
-    }
-}
-
-impl DerefMut for MySqlArguments {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.values
+        self.add(value)
     }
 }
diff --git a/sqlx-core/src/mysql/protocol/statement/execute.rs b/sqlx-core/src/mysql/protocol/statement/execute.rs
index 2186a927b..e97cc1213 100644
--- a/sqlx-core/src/mysql/protocol/statement/execute.rs
+++ b/sqlx-core/src/mysql/protocol/statement/execute.rs
@@ -18,7 +18,7 @@ impl<'q> Encode<'_, Capabilities> for Execute<'q> {
         buf.push(0); // NO_CURSOR
         buf.extend(&0_u32.to_le_bytes()); // iterations (always 1): int<4>
 
-        if !self.arguments.is_empty() {
+        if !self.arguments.values.is_empty() {
             buf.extend(&*self.arguments.null_bitmap);
             buf.push(1); // send type to server
 
diff --git a/sqlx-core/src/postgres/arguments.rs b/sqlx-core/src/postgres/arguments.rs
index ed379d14e..9d98470d3 100644
--- a/sqlx-core/src/postgres/arguments.rs
+++ b/sqlx-core/src/postgres/arguments.rs
@@ -31,6 +31,20 @@ pub struct PgArguments {
     pub(crate) buffer: PgArgumentBuffer,
 }
 
+impl PgArguments {
+    pub(crate) fn add<'q, T>(&mut self, value: T)
+    where
+        T: Encode<'q, Postgres> + Type<Postgres>,
+    {
+        // remember the type information for this value
+        self.types
+            .push(value.produces().unwrap_or_else(T::type_info));
+
+        // encode the value into our buffer
+        self.buffer.encode(value);
+    }
+}
+
 impl<'q> Arguments<'q> for PgArguments {
     type Database = Postgres;
 
@@ -43,12 +57,7 @@ impl<'q> Arguments<'q> for PgArguments {
     where
         T: Encode<'q, Self::Database> + Type<Self::Database>,
     {
-        // remember the type information for this value
-        self.types
-            .push(value.produces().unwrap_or_else(T::type_info));
-
-        // encode the value into our buffer
-        self.buffer.encode(value);
+        self.add(value)
     }
 }
 
diff --git a/sqlx-core/src/postgres/connection/describe.rs b/sqlx-core/src/postgres/connection/describe.rs
index b9aa96511..cfbb1cb69 100644
--- a/sqlx-core/src/postgres/connection/describe.rs
+++ b/sqlx-core/src/postgres/connection/describe.rs
@@ -5,7 +5,6 @@ use std::sync::Arc;
 use futures_util::{stream, StreamExt, TryStreamExt};
 use hashbrown::HashMap;
 
-use crate::arguments::Arguments;
 use crate::describe::Column;
 use crate::error::Error;
 use crate::ext::ustr::UStr;
@@ -22,8 +21,6 @@ impl PgConnection {
         &mut self,
         desc: Option<RowDescription>,
         should_fetch: bool,
-        // columns: &mut Vec<PgColumn>,
-        // column_names: &mut HashMap<UStr, usize>,
     ) -> Result<(), Error> {
         let mut columns = Vec::new();
         let mut column_names = HashMap::new();
diff --git a/sqlx-core/src/sqlite/arguments.rs b/sqlx-core/src/sqlite/arguments.rs
index e773d2447..7ae9b6fea 100644
--- a/sqlx-core/src/sqlite/arguments.rs
+++ b/sqlx-core/src/sqlite/arguments.rs
@@ -24,6 +24,17 @@ pub struct SqliteArguments<'q> {
     pub(crate) values: Vec<SqliteArgumentValue<'q>>,
 }
 
+impl<'q> SqliteArguments<'q> {
+    pub(crate) fn add<T>(&mut self, value: T)
+    where
+        T: Encode<'q, Sqlite>,
+    {
+        if let IsNull::Yes = value.encode(&mut self.values) {
+            self.values.push(SqliteArgumentValue::Null);
+        }
+    }
+}
+
 impl<'q> Arguments<'q> for SqliteArguments<'q> {
     type Database = Sqlite;
 
@@ -33,11 +44,9 @@ impl<'q> Arguments<'q> for SqliteArguments<'q> {
 
     fn add<T>(&mut self, value: T)
     where
-        T: 'q + Encode<'q, Self::Database>,
+        T: Encode<'q, Self::Database>,
     {
-        if let IsNull::Yes = value.encode(&mut self.values) {
-            self.values.push(SqliteArgumentValue::Null);
-        }
+        self.add(value)
     }
 }