diff --git a/src/NQuery.Tests/Evaluation/EvaluationTest.cs b/src/NQuery.Tests/Evaluation/EvaluationTest.cs
index 32b1f3f3..cc882ac7 100644
--- a/src/NQuery.Tests/Evaluation/EvaluationTest.cs
+++ b/src/NQuery.Tests/Evaluation/EvaluationTest.cs
@@ -1,8 +1,8 @@
 namespace NQuery.Tests.Evaluation
 {
-    public class EvaluationTest
+    public abstract class EvaluationTest
     {
-        protected static void AssertProduces<T>(string text, T[] expected)
+        protected static void AssertProduces<T>(string text, T[] expected, DataContext dataContext = null)
         {
             var expectedColumns = new[] { typeof(T) };
             var expectedRows = new object[expected.Length][];
@@ -10,10 +10,10 @@ protected static void AssertProduces<T>(string text, T[] expected)
             for (var i = 0; i < expected.Length; i++)
                 expectedRows[i] = new object[] { expected[i] };
 
-            AssertProduces(text, expectedColumns, expectedRows);
+            AssertProduces(text, expectedColumns, expectedRows, dataContext);
         }
 
-        protected static void AssertProduces<T1, T2>(string text, (T1, T2)[] expected)
+        protected static void AssertProduces<T1, T2>(string text, (T1, T2)[] expected, DataContext dataContext = null)
         {
             var expectedColumns = new[] { typeof(T1), typeof(T2) };
             var expectedRows = new object[expected.Length][];
@@ -21,12 +21,12 @@ protected static void AssertProduces<T1, T2>(string text, (T1, T2)[] expected)
             for (var i = 0; i < expected.Length; i++)
                 expectedRows[i] = new object[] { expected[i].Item1, expected[i].Item2 };
 
-            AssertProduces(text, expectedColumns, expectedRows);
+            AssertProduces(text, expectedColumns, expectedRows, dataContext);
         }
 
-        private static void AssertProduces(string text, Type[] expectedColumns, object[][] expectedRows)
+        private static void AssertProduces(string text, Type[] expectedColumns, object[][] expectedRows, DataContext dataContext)
         {
-            var dataContext = NorthwindDataContext.Instance;
+            dataContext ??= NorthwindDataContext.Instance;
             var query = Query.Create(dataContext, text);
             using var data = query.ExecuteReader();
 
diff --git a/src/NQuery.Tests/Evaluation/FunctionInvocationTests.cs b/src/NQuery.Tests/Evaluation/FunctionInvocationTests.cs
new file mode 100644
index 00000000..487066b3
--- /dev/null
+++ b/src/NQuery.Tests/Evaluation/FunctionInvocationTests.cs
@@ -0,0 +1,91 @@
+using NQuery.Symbols;
+
+namespace NQuery.Tests.Evaluation
+{
+    public sealed class FunctionInvocationTests : EvaluationTest
+    {
+        private readonly DataContext _dataContext;
+
+        public FunctionInvocationTests()
+        {
+            _dataContext = DataContext.Default.AddFunctions(
+                new FunctionSymbol<int>(nameof(StaticFunction0), StaticFunction0),
+                new FunctionSymbol<int, int>(nameof(StaticFunction1), StaticFunction1),
+                new FunctionSymbol<int, int, int>(nameof(StaticFunction2), StaticFunction2),
+                new FunctionSymbol<int, int, int, int>(nameof(StaticFunction3), StaticFunction3),
+                new FunctionSymbol<int>(nameof(InstanceFunction0), InstanceFunction0),
+                new FunctionSymbol<int, int>(nameof(InstanceFunction1), InstanceFunction1),
+                new FunctionSymbol<int, int, int>(nameof(InstanceFunction2), InstanceFunction2),
+                new FunctionSymbol<int, int, int, int>(nameof(InstanceFunction3), InstanceFunction3)
+            );
+        }
+
+        [Theory]
+        [InlineData(nameof(StaticFunction0) + "()")]
+        [InlineData(nameof(StaticFunction1) + "(42)")]
+        [InlineData(nameof(StaticFunction2) + "(40, 2)")]
+        [InlineData(nameof(StaticFunction3) + "(20, 20, 2)")]
+        public void Evaluation_FunctionInvocationExpression_StaticFunction(string functionInvocation)
+        {
+            var text = "SELECT " + functionInvocation;
+
+            var expected = new[] { 42 };
+
+            AssertProduces(text, expected, _dataContext);
+        }
+
+        [Theory]
+        [InlineData(nameof(InstanceFunction0) + "()")]
+        [InlineData(nameof(InstanceFunction1) + "(42)")]
+        [InlineData(nameof(InstanceFunction2) + "(40, 2)")]
+        [InlineData(nameof(InstanceFunction3) + "(20, 20, 2)")]
+        public void Evaluation_FunctionInvocationExpression_InstanceFunction(string functionInvocation)
+        {
+            var text = "SELECT " + functionInvocation;
+
+            var expected = new[] { GetHashCode() + 42 };
+
+            AssertProduces(text, expected, _dataContext);
+        }
+
+        private static int StaticFunction0()
+        {
+            return 42;
+        }
+
+        private static int StaticFunction1(int arg)
+        {
+            return arg;
+        }
+
+        private static int StaticFunction2(int arg1, int arg2)
+        {
+            return arg1 + arg2;
+        }
+
+        private static int StaticFunction3(int arg1, int arg2, int arg3)
+        {
+            return arg1 + arg2 + arg3;
+        }
+
+        private int InstanceFunction0()
+        {
+            return GetHashCode() + 42;
+        }
+
+        private int InstanceFunction1(int arg)
+        {
+            return GetHashCode() + arg;
+        }
+
+        private int InstanceFunction2(int arg1, int arg2)
+        {
+            return GetHashCode() + arg1 + arg2;
+        }
+
+        private int InstanceFunction3(int arg1, int arg2, int arg3)
+        {
+            return GetHashCode() + arg1 + arg2 + arg3;
+        }
+    }
+}
diff --git a/src/NQuery/Symbols/FunctionSymbol.cs b/src/NQuery/Symbols/FunctionSymbol.cs
index 28a4c5a6..260db174 100644
--- a/src/NQuery/Symbols/FunctionSymbol.cs
+++ b/src/NQuery/Symbols/FunctionSymbol.cs
@@ -14,12 +14,19 @@ protected FunctionSymbol(string name, Type type, params ParameterSymbol[] parame
         {
         }
 
-        public abstract Expression CreateInvocation(IEnumerable<Expression> arguments);
+        public Expression CreateInvocation(IEnumerable<Expression> arguments)
+        {
+            var function = FunctionDelegate;
+            var instance = function.Target == null ? null : Expression.Constant(function.Target);
+            return Expression.Call(instance, function.Method, arguments);
+        }
 
         public override SymbolKind Kind
         {
             get { return SymbolKind.Function; }
         }
+
+        protected abstract Delegate FunctionDelegate { get; }
     }
 
     public sealed class FunctionSymbol<TResult> : FunctionSymbol
@@ -30,12 +37,12 @@ public FunctionSymbol(string name, Func<TResult> function)
             Function = function;
         }
 
-        public override Expression CreateInvocation(IEnumerable<Expression> arguments)
+        public Func<TResult> Function { get; }
+
+        protected override Delegate FunctionDelegate
         {
-            return Expression.Call(Function.Method, arguments);
+            get { return Function; }
         }
-
-        public Func<TResult> Function { get; }
     }
 
     public sealed class FunctionSymbol<T, TResult> : FunctionSymbol
@@ -52,12 +59,12 @@ public FunctionSymbol(string name, string argumentName, Func<T, TResult> functio
             Function = function;
         }
 
-        public override Expression CreateInvocation(IEnumerable<Expression> arguments)
+        public Func<T, TResult> Function { get; }
+
+        protected override Delegate FunctionDelegate
         {
-            return Expression.Call(Function.Method, arguments);
+            get { return Function; }
         }
-
-        public Func<T, TResult> Function { get; }
     }
 
     public sealed class FunctionSymbol<T1, T2, TResult> : FunctionSymbol
@@ -73,12 +80,12 @@ public FunctionSymbol(string name, string parameterName1, string parameterName2,
             Function = function;
         }
 
-        public override Expression CreateInvocation(IEnumerable<Expression> arguments)
+        public Func<T1, T2, TResult> Function { get; }
+
+        protected override Delegate FunctionDelegate
         {
-            return Expression.Call(Function.Method, arguments);
+            get { return Function; }
         }
-
-        public Func<T1, T2, TResult> Function { get; }
     }
 
     public sealed class FunctionSymbol<T1, T2, T3, TResult> : FunctionSymbol
@@ -94,11 +101,11 @@ public FunctionSymbol(string name, string parameterName1, string parameterName2,
             Function = function;
         }
 
-        public override Expression CreateInvocation(IEnumerable<Expression> arguments)
+        public Func<T1, T2, T3, TResult> Function { get; }
+
+        protected override Delegate FunctionDelegate
         {
-            return Expression.Call(Function.Method, arguments);
+            get { return Function; }
         }
-
-        public Func<T1, T2, T3, TResult> Function { get; }
     }
 }
\ No newline at end of file