diff --git a/lexer/lexer.mll b/lexer/lexer.mll
index 4116cb7..405ce52 100644
--- a/lexer/lexer.mll
+++ b/lexer/lexer.mll
@@ -22,6 +22,8 @@ rule read_token = parse
   | "UNION"     { UNION }
   | "JOIN"      { JOIN }
   | "ON"        { ON }
+  | "WHERE"     { WHERE }
+  | "HAVING"    { HAVING }
   | "GROUP"     { GROUP }
   | "BY"        { BY }
   | "*"         { ASTERISK }
@@ -31,6 +33,5 @@ rule read_token = parse
   | ")"         { RIGHT_PAREN }
   | ","         { COMMA }
   | whitespace  { read_token lexbuf }
-  | "WHERE"     { WHERE }
   | alpha alphanumeric* as ident      { IDENT ident }
   | eof         { EOF }
diff --git a/lib/ast.ml b/lib/ast.ml
index 5debe2f..ce4839e 100644
--- a/lib/ast.ml
+++ b/lib/ast.ml
@@ -16,12 +16,13 @@ and join_type =
   | Union
   | Natural
 and condition = 
-  | Condition of string * comparison
+  | Condition of string * predicate
   | And of condition * condition
   | Or of condition * condition
   | Not of condition
-and comparison = 
+and predicate = 
   | Comparison of operator * string
+  | Between of string * string
 and operator =
   | Equals
   | NotEquals
@@ -29,5 +30,7 @@ and operator =
   | GreaterThan
   | LessEquals
   | GreaterEquals
+and filter = 
+  | Filter of string
 and search_condition =
   | Search of string
diff --git a/lib/logical_plan.ml b/lib/logical_plan.ml
index db81796..7337ac3 100644
--- a/lib/logical_plan.ml
+++ b/lib/logical_plan.ml
@@ -1,17 +1,13 @@
 type logical_plan =
   | Scan of string (* Table name *)
-  (*| Filter of logical_plan * condition*)
+  | Filter of logical_plan * condition
   | Join of logical_plan * Ast.join_type * logical_plan 
+and condition = 
+  | Condition of string
 
-let rec generate_logical_plan ast =
-  match ast with 
-  | Ast.Query(Select(_, tables)) -> 
-      let base_plan = generate_from_clause tables in
-      base_plan
-
-and generate_from_clause tables =
+let rec generate_from_clause tables =
   match tables with
-  | [Table(name)] -> Scan(name)
+  | [Ast.Table(name)] -> Scan(name)
   | [Ast.Join(left, j_type, right, _)] -> 
       Join(
         generate_from_clause [left],
@@ -21,6 +17,12 @@ and generate_from_clause tables =
   | _ -> failwith "Unsupported table structure"
 
 
+let generate_logical_plan ast =
+  match ast with 
+  | Ast.Query(Select(_, tables)) -> 
+      let base_plan = generate_from_clause tables in
+      base_plan
+
 (*let evaluate_plan plan =
   match plan with
   | Scan(table) -> 
diff --git a/parser/parser.mly b/parser/parser.mly
index c72b6d4..4907d70 100644
--- a/parser/parser.mly
+++ b/parser/parser.mly
@@ -3,11 +3,12 @@
 open Ast
 %}
 
-%token SELECT ALL DISTINCT FROM WHERE
+%token SELECT ALL DISTINCT FROM WHERE HAVING BETWEEN
 %token LEFT RIGHT FULL INNER OUTER
 %token CROSS NATURAL  UNION JOIN
 %token GREATER_THAN_OPERATOR LESS_THAN_OPERATOR EQUALS_OPERATOR
 %token MAX MIN SUM COUNT AVG
+%token ASYMMETRIC SYMMETRIC
 %token <string> IDENT
 %token COMMA DOT
 %token LEFT_PAREN RIGHT_PAREN
@@ -130,10 +131,12 @@ outer_join_type:
   | RIGHT { Right }
   | FULL { Full }
 
-
 where_clause : 
   | WHERE search_condition { }
 
+having_clause :
+  | HAVING search_condition {}
+
 search_condition:
   (*| IDENT EQUALS_OPERATOR IDENT {}*)
   | boolean_value_expression { $1 }
@@ -159,6 +162,7 @@ boolean_primary :
 
 predicate :
   | comparison_predicate { $1 }
+(*  | between_predicate { $1 }*)
 
 comparison_predicate :
   | row_value_predicand comparison_predicate_part2 { Condition($1, $2) }
@@ -166,6 +170,18 @@ comparison_predicate :
 comparison_predicate_part2:
   | comp_op row_value_predicand { Comparison($1, $2) }
 
+between_predicate :
+  | row_value_predicand between_predicate_part2 { }
+
+between_predicate_part2 :
+  | BETWEEN between_symetry row_value_predicand AND row_value_predicand {}
+  | NOT BETWEEN between_symetry  row_value_predicand AND row_value_predicand {}
+
+between_symetry :
+  | {} 
+  | ASYMMETRIC {}
+  | SYMMETRIC {}
+
 comp_op :
   | EQUALS_OPERATOR { Equals }
   | not_equals_operator { NotEquals }
diff --git a/test/logical_plan_test.ml b/test/logical_plan_test.ml
index 9e1ffea..6226d9e 100644
--- a/test/logical_plan_test.ml
+++ b/test/logical_plan_test.ml
@@ -11,4 +11,3 @@ let () =
       Logical_plan.Scan("t2")
     )
   );
-