diff --git a/lib/context.js b/lib/context.js
index 3afbe1a..af1fe98 100644
--- a/lib/context.js
+++ b/lib/context.js
@@ -62,10 +62,11 @@ class Context {
      * @param {string}                  table
      * @param {Object|Array.<Object>}   data
      * @param {Array.<string>|Object}   update
+     * @param {?string}                 [alias=new]
      * @return {Promise}
      */
-    upsert(table, data, update) {
-        const sql = upsertStmt(table, data, update);
+    upsert(table, data, update, alias = 'new') {
+        const sql = upsertStmt(table, data, update, alias);
         return this.exec(sql);
     }
 
diff --git a/lib/transaction.js b/lib/transaction.js
index 1c4db16..fe42bac 100644
--- a/lib/transaction.js
+++ b/lib/transaction.js
@@ -67,10 +67,11 @@ class Transaction {
      * @param {string}                  table
      * @param {Object|Array.<Object>}   data
      * @param {Array.<string>|Object}   update
+     * @param {?string}                 [alias=new]
      * @return {Promise}
      */
-    upsert(table, data, update) {
-        const sql = upsertStmt(table, data, update);
+    upsert(table, data, update, alias = 'new') {
+        const sql = upsertStmt(table, data, update, alias);
         return this.exec(sql).then(({ affectedRows, changedRows }) => ({ affectedRows, changedRows }));
     }
 
diff --git a/lib/util.js b/lib/util.js
index 31ee3bb..ff0d663 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -133,14 +133,15 @@ function deleteStmt(table, where) {
  * @param {string}                  table
  * @param {Object|Array.<Object>}   data
  * @param {Array.<string>|Object}   update
+ * @param {string}                  alias
  * @return {string}
  */
-function upsertStmt(table, data, update) {
+function upsertStmt(table, data, update, alias) {
     if (!update || typeof update !== 'object') {
         throw new ImplementationError('Update parameter must be either an object or an array of strings');
     }
 
-    const sql = insertStmt(table, data) + ' ON DUPLICATE KEY UPDATE ';
+    const sql = `${insertStmt(table, data)} AS ${escapeId(alias)} ON DUPLICATE KEY UPDATE `;
 
     if (!Array.isArray(update) && isIterable(update)) {
         return (
@@ -152,7 +153,7 @@ function upsertStmt(table, data, update) {
     }
 
     if (Array.isArray(update) && update.every((item) => typeof item === 'string')) {
-        return sql + update.map((column) => escapeId(column) + ' = VALUES(' + escapeId(column) + ')').join(', ');
+        return sql + update.map((column) => `${escapeId(column)} = ${escapeId(alias)}.${escapeId(column)}`).join(', ');
     }
 
     return sql;
diff --git a/test/integration/transaction.spec.js b/test/integration/transaction.spec.js
index 3b2ff0a..5a964f6 100644
--- a/test/integration/transaction.spec.js
+++ b/test/integration/transaction.spec.js
@@ -175,11 +175,15 @@ describe('transaction', () => {
             await ctx.exec(`CREATE TABLE ${table} (id INT PRIMARY KEY, col1 VARCHAR(32))`);
             await ctx.transaction(async (trx) => {
                 await trx.insert(table, { id: 1, col1: 'foo' });
-                await trx.upsert(table, { id: 1, col1: 'bar' }, { col1: ctx.raw('MD5(col1)') });
+                await trx.upsert(
+                    table,
+                    { id: 1, col1: 'bar' },
+                    { col1: ctx.raw(`CONCAT(${table}.col1, \`new\`.col1)`) }
+                );
             });
 
-            const hash = await ctx.queryOne(`SELECT col1 FROM ${table} WHERE id = 1`);
-            assert.equal(hash, 'acbd18db4cc2f85cedef654fccc4a4d8');
+            const value = await ctx.queryOne(`SELECT col1 FROM ${table} WHERE id = 1`);
+            assert.equal(value, 'foobar');
         });
 
         it('should accept updates as an array', async () => {
diff --git a/test/unit/context.spec.js b/test/unit/context.spec.js
index 88dd5ed..41d9669 100644
--- a/test/unit/context.spec.js
+++ b/test/unit/context.spec.js
@@ -334,20 +334,34 @@ describe('context', () => {
 
             const [call] = ctx.exec.mock.calls;
             assert.deepEqual(call.arguments, [
-                `INSERT INTO \`t\` (\`col1\`, \`col2\`, \`col3\`) VALUES ('val1', 1, NOW()) ON DUPLICATE KEY UPDATE \`col1\` = VALUES(\`col1\`), \`col2\` = VALUES(\`col2\`)`
+                `INSERT INTO \`t\` (\`col1\`, \`col2\`, \`col3\`) VALUES ('val1', 1, NOW()) AS \`new\` ON DUPLICATE KEY UPDATE \`col1\` = \`new\`.\`col1\`, \`col2\` = \`new\`.\`col2\``
             ]);
         });
 
         it('should accept assignment list as an object', async () => {
-            await ctx.upsert(
-                't',
-                { col1: 'val1', col2: 1, col3: ctx.raw('NOW()') },
-                { col1: 'foo', col2: ctx.raw(ctx.quoteIdentifier('col2') + ' + 1') }
-            );
+            await ctx.upsert('t', { col1: 'val1', col2: 1, col3: ctx.raw('NOW()') }, { col1: 'foo' });
 
             const [call] = ctx.exec.mock.calls;
             assert.deepEqual(call.arguments, [
-                `INSERT INTO \`t\` (\`col1\`, \`col2\`, \`col3\`) VALUES ('val1', 1, NOW()) ON DUPLICATE KEY UPDATE \`col1\` = 'foo', \`col2\` = \`col2\` + 1`
+                `INSERT INTO \`t\` (\`col1\`, \`col2\`, \`col3\`) VALUES ('val1', 1, NOW()) AS \`new\` ON DUPLICATE KEY UPDATE \`col1\` = 'foo'`
+            ]);
+        });
+
+        it('must not use alias for raw values', async () => {
+            await ctx.upsert('t', { id: 1, ts: '2000-01-01 00:00:00' }, { ts: ctx.raw('NOW()') });
+
+            const [call] = ctx.exec.mock.calls;
+            assert.deepEqual(call.arguments, [
+                `INSERT INTO \`t\` (\`id\`, \`ts\`) VALUES (1, '2000-01-01 00:00:00') AS \`new\` ON DUPLICATE KEY UPDATE \`ts\` = NOW()`
+            ]);
+        });
+
+        it('should support custom alias', async () => {
+            await ctx.upsert('t', { id: 1, col1: 'val1' }, ['col1'], 'funkyAlias');
+
+            const [call] = ctx.exec.mock.calls;
+            assert.deepEqual(call.arguments, [
+                `INSERT INTO \`t\` (\`id\`, \`col1\`) VALUES (1, 'val1') AS \`funkyAlias\` ON DUPLICATE KEY UPDATE \`col1\` = \`funkyAlias\`.\`col1\``
             ]);
         });
     });