diff --git a/src/lib/Expr.cpp b/src/lib/Expr.cpp
index 6407d24..c919ec4 100644
--- a/src/lib/Expr.cpp
+++ b/src/lib/Expr.cpp
@@ -78,10 +78,11 @@ Expr* Expr::makeColumnRef(char* table, char* name) {
 	return e;
 }
 
-Expr* Expr::makeFunctionRef(char* func_name, Expr* expr) {
+Expr* Expr::makeFunctionRef(char* func_name, Expr* expr, bool distinct) {
 	Expr* e = new Expr(kExprFunctionRef);
 	e->name = func_name;
 	e->expr = expr;
+	e->distinct = distinct;
 	return e;
 }
 
diff --git a/src/lib/Expr.h b/src/lib/Expr.h
index 709521b..4588c80 100644
--- a/src/lib/Expr.h
+++ b/src/lib/Expr.h
@@ -22,6 +22,7 @@ typedef enum {
 	kExprOperator
 } ExprType;
 
+
 typedef struct Expr Expr;
 
 /** 
@@ -79,6 +80,7 @@ struct Expr {
 
 	OperatorType op_type;
 	char op_char;
+	bool distinct;
 
 
 	/**
@@ -109,7 +111,7 @@ struct Expr {
 
 	static Expr* makeColumnRef(char* name);
 	static Expr* makeColumnRef(char* table, char* name);
-	static Expr* makeFunctionRef(char* func_name, Expr* expr);
+	static Expr* makeFunctionRef(char* func_name, Expr* expr, bool distinct);
 };
 
 // Zero initializes an Expr object and assigns it to a space in the heap
diff --git a/src/lib/statements/SelectStatement.h b/src/lib/statements/SelectStatement.h
index 008618d..a9788a6 100644
--- a/src/lib/statements/SelectStatement.h
+++ b/src/lib/statements/SelectStatement.h
@@ -93,6 +93,7 @@ struct SelectStatement : SQLStatement {
 	}
 
 	TableRef* from_table;
+	bool select_distinct;
 	List<Expr*>* select_list;
 	Expr* where_clause;	
 	GroupByDescription* group_by;
diff --git a/src/parser/bison_parser.y b/src/parser/bison_parser.y
index ffb58f7..874c4d6 100644
--- a/src/parser/bison_parser.y
+++ b/src/parser/bison_parser.y
@@ -171,7 +171,7 @@ int yyerror(YYLTYPE* llocp, SQLStatementList** result, yyscan_t scanner, const c
 %type <update_stmt> update_statement
 %type <drop_stmt>	drop_statement
 %type <sval> 		table_name opt_alias alias file_path
-%type <bval> 		opt_not_exists
+%type <bval> 		opt_not_exists opt_distinct
 %type <uval>		import_file_type opt_join_type column_type
 %type <table> 		from_clause table_ref table_ref_atomic table_ref_name
 %type <table>		join_clause join_table table_ref_name_no_alias
@@ -455,15 +455,20 @@ set_operator:
 	;
 
 select_clause:
-		SELECT select_list from_clause opt_where opt_group {
+		SELECT opt_distinct select_list from_clause opt_where opt_group {
 			$$ = new SelectStatement();
-			$$->select_list = $2;
-			$$->from_table = $3;
-			$$->where_clause = $4;
-			$$->group_by = $5;
+			$$->select_distinct = $2;
+			$$->select_list = $3;
+			$$->from_table = $4;
+			$$->where_clause = $5;
+			$$->group_by = $6;
 		}
 	;
 
+opt_distinct:
+		DISTINCT { $$ = true; }
+	|	/* empty */ { $$ = false; }
+	;
 
 select_list:
 		expr_list
@@ -576,7 +581,7 @@ comp_expr:
 	;
 
 function_expr:
-		IDENTIFIER '(' expr ')' { $$ = Expr::makeFunctionRef($1, $3); }
+		IDENTIFIER '(' opt_distinct expr ')' { $$ = Expr::makeFunctionRef($1, $4, $3); }
 	;
 
 column_name:
diff --git a/src/tests/select.cpp b/src/tests/select.cpp
index 74a71bb..e30f5c8 100644
--- a/src/tests/select.cpp
+++ b/src/tests/select.cpp
@@ -16,6 +16,7 @@ TEST(SelectTest) {
 
 TEST(SelectHavingTest) {
 	TEST_PARSE_SINGLE_SQL("SELECT city, AVG(grade) AS avg_grade FROM students GROUP BY city HAVING AVG(grade) < 2.0", kStmtSelect, SelectStatement, stmt);
+	ASSERT_FALSE(stmt->select_distinct);
 
 	GroupByDescription* group = stmt->group_by;
 	ASSERT_NOTNULL(group);
@@ -28,12 +29,18 @@ TEST(SelectHavingTest) {
 
 TEST(SelectDistinctTest) {
 	TEST_PARSE_SINGLE_SQL("SELECT DISTINCT grade, city FROM students;", kStmtSelect, SelectStatement, stmt);
+
+	ASSERT(stmt->select_distinct);
 	ASSERT_NULL(stmt->where_clause);
 }
 
 TEST(SelectGroupDistinctTest) {
-	TEST_PARSE_SINGLE_SQL("SELECT city, COUNT(DISTINCT name), SUM(DISTINCT grade) FROM students GROUP BY city;", kStmtSelect, SelectStatement, stmt);
-	ASSERT_NULL(stmt->where_clause);
+	TEST_PARSE_SINGLE_SQL("SELECT city, COUNT(name), COUNT(DISTINCT grade) FROM students GROUP BY city;", kStmtSelect, SelectStatement, stmt);
+
+	ASSERT_FALSE(stmt->select_distinct);
+	ASSERT_EQ(stmt->select_list->size(), 3);
+	ASSERT(!stmt->select_list->at(1)->distinct);
+	ASSERT(stmt->select_list->at(2)->distinct);
 }