diff --git a/mocha.start.js b/mocha.start.js
index 5b39dad..d41cb84 100644
--- a/mocha.start.js
+++ b/mocha.start.js
@@ -25,6 +25,10 @@ if (DB_CLIENT === 'sqlite3') {
     user: process.env.DB_USER || 'root',
     database: process.env.DB_NAME || 'test'
   }
+
+  if (process.env.DB_PASS) {
+    connection.password = process.env.DB_PASS
+  }
 }
 
 JSDataAdapterTests.init({
diff --git a/src/index.js b/src/index.js
index 2d21b16..61641d0 100644
--- a/src/index.js
+++ b/src/index.js
@@ -421,6 +421,13 @@ function loadWithRelations (items, resourceConfig, options) {
 Adapter.extend({
   constructor: SqlAdapter,
 
+  _returning (idAttribute) {
+    // Some knex client drivers do not support .returning(), so set the
+    // attribute to null to prevent knex from emitting warnings.
+
+    return ['mysql', 'sqlite3'].includes(this.knexOpts.client) ? null : idAttribute
+  },
+
   _count (mapper, query, opts) {
     opts || (opts = {})
     query || (query = {})
@@ -438,7 +445,7 @@ Adapter.extend({
 
     const sqlBuilder = utils.isUndefined(opts.transaction) ? this.knex : opts.transaction
     return sqlBuilder(getTable(mapper))
-      .insert(props, idAttribute)
+      .insert(props, this._returning(idAttribute))
       .then((ids) => {
         const id = utils.isUndefined(props[idAttribute]) ? (ids.length ? ids[0] : undefined) : props[idAttribute]
         if (utils.isUndefined(id)) {
diff --git a/test/knexfile.js b/test/knexfile.js
index 3e7cf4a..22f5d75 100644
--- a/test/knexfile.js
+++ b/test/knexfile.js
@@ -9,8 +9,12 @@ if (DB_CLIENT === 'sqlite3') {
 } else {
   connection = {
     host: process.env.DB_HOST || '127.0.0.1',
-    user: process.env.DB_USER,
-    database: process.env.DB_NAME
+    user: process.env.DB_USER || 'root',
+    database: process.env.DB_NAME || 'test'
+  }
+
+  if (process.env.DB_PASS) {
+    connection.password = process.env.DB_PASS
   }
 }