diff --git a/lykiadb-lang/src/ast/expr.rs b/lykiadb-lang/src/ast/expr.rs
index fd24b10..fc1f7e1 100644
--- a/lykiadb-lang/src/ast/expr.rs
+++ b/lykiadb-lang/src/ast/expr.rs
@@ -13,7 +13,7 @@ use super::{
 
 use crate::Literal;
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, Hash)]
 #[serde(tag = "@type")]
 pub enum Operation {
     Add,
@@ -37,7 +37,7 @@ pub enum Operation {
     NotLike,
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, Hash)]
 #[serde(tag = "@type")]
 pub enum RangeKind {
     Between,
@@ -46,16 +46,18 @@ pub enum RangeKind {
 
 #[derive(Debug, Serialize, Deserialize, Clone, Derivative)]
 #[serde(tag = "@type")]
-#[derivative(Eq, PartialEq)]
+#[derivative(Eq, PartialEq, Hash)]
 pub enum Expr {
     #[serde(rename = "Expr::Select")]
     Select {
         query: SqlSelect,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Insert")]
@@ -63,9 +65,11 @@ pub enum Expr {
         command: SqlInsert,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Update")]
@@ -73,9 +77,11 @@ pub enum Expr {
         command: SqlUpdate,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Delete")]
@@ -83,9 +89,11 @@ pub enum Expr {
         command: SqlDelete,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Variable")]
@@ -93,9 +101,11 @@ pub enum Expr {
         name: Identifier,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Grouping")]
@@ -103,9 +113,11 @@ pub enum Expr {
         expr: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Literal")]
@@ -114,9 +126,11 @@ pub enum Expr {
         raw: String,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Function")]
@@ -126,9 +140,11 @@ pub enum Expr {
         body: Arc<Vec<Stmt>>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Between")]
@@ -139,9 +155,11 @@ pub enum Expr {
         kind: RangeKind,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Binary")]
@@ -151,9 +169,11 @@ pub enum Expr {
         right: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Unary")]
@@ -162,9 +182,11 @@ pub enum Expr {
         expr: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Assignment")]
@@ -173,9 +195,11 @@ pub enum Expr {
         expr: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Logical")]
@@ -185,9 +209,11 @@ pub enum Expr {
         right: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Call")]
@@ -196,9 +222,11 @@ pub enum Expr {
         args: Vec<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Get")]
@@ -207,9 +235,11 @@ pub enum Expr {
         name: Identifier,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
     #[serde(rename = "Expr::Set")]
@@ -219,9 +249,11 @@ pub enum Expr {
         value: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         id: usize,
     },
 }
diff --git a/lykiadb-lang/src/ast/sql.rs b/lykiadb-lang/src/ast/sql.rs
index 30e09f3..e8cfd61 100644
--- a/lykiadb-lang/src/ast/sql.rs
+++ b/lykiadb-lang/src/ast/sql.rs
@@ -5,7 +5,7 @@ use super::expr::Expr;
 
 // Enums
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlDistinct {
     #[serde(rename = "SqlDistinct::ImplicitAll")]
@@ -16,7 +16,7 @@ pub enum SqlDistinct {
     Distinct,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlJoinType {
     #[serde(rename = "SqlJoinType::Left")]
@@ -29,7 +29,7 @@ pub enum SqlJoinType {
     Cross,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlCompoundOperator {
     #[serde(rename = "SqlCompoundOperator::Union")]
@@ -42,7 +42,7 @@ pub enum SqlCompoundOperator {
     Except,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlOrdering {
     #[serde(rename = "SqlOrdering::Asc")]
@@ -52,7 +52,7 @@ pub enum SqlOrdering {
 }
 
 //
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlCollectionIdentifier {
     pub namespace: Option<Identifier>,
@@ -60,7 +60,7 @@ pub struct SqlCollectionIdentifier {
     pub alias: Option<Identifier>,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlProjection {
     #[serde(rename = "SqlProjection::All")]
@@ -72,28 +72,28 @@ pub enum SqlProjection {
     },
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlLimitClause {
     pub count: Box<Expr>,
     pub offset: Option<Box<Expr>>,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlOrderByClause {
     pub expr: Box<Expr>,
     pub ordering: SqlOrdering,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlSelectCompound {
     pub operator: SqlCompoundOperator,
     pub core: SqlSelectCore,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlFrom {
     #[serde(rename = "SqlFrom::Group")]
@@ -114,7 +114,7 @@ pub enum SqlFrom {
     },
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlSelectCore {
     pub distinct: SqlDistinct,
@@ -126,7 +126,7 @@ pub struct SqlSelectCore {
     pub compound: Option<Box<SqlSelectCompound>>,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlSelect {
     pub core: SqlSelectCore,
@@ -134,7 +134,7 @@ pub struct SqlSelect {
     pub limit: Option<SqlLimitClause>,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub enum SqlValues {
     #[serde(rename = "SqlValues::Values")]
@@ -143,14 +143,14 @@ pub enum SqlValues {
     Select(SqlSelect),
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlInsert {
     pub collection: SqlCollectionIdentifier,
     pub values: SqlValues,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlUpdate {
     pub collection: SqlCollectionIdentifier,
@@ -158,7 +158,7 @@ pub struct SqlUpdate {
     pub r#where: Option<Box<Expr>>,
 }
 
-#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone)]
+#[derive(Debug, Eq, PartialEq, Serialize, Deserialize, Clone, Hash)]
 #[serde(tag = "@type")]
 pub struct SqlDelete {
     pub collection: SqlCollectionIdentifier,
diff --git a/lykiadb-lang/src/ast/stmt.rs b/lykiadb-lang/src/ast/stmt.rs
index 99ca5be..f109aea 100644
--- a/lykiadb-lang/src/ast/stmt.rs
+++ b/lykiadb-lang/src/ast/stmt.rs
@@ -7,13 +7,14 @@ use super::expr::Expr;
 
 #[derive(Debug, Serialize, Deserialize, Clone, Derivative)]
 #[serde(tag = "@type")]
-#[derivative(Eq, PartialEq)]
+#[derivative(Eq, PartialEq, Hash)]
 pub enum Stmt {
     #[serde(rename = "Stmt::Program")]
     Program {
         body: Vec<Stmt>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Expression")]
@@ -21,18 +22,21 @@ pub enum Stmt {
         expr: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Break")]
     Break {
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Continue")]
     Continue {
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Block")]
@@ -40,6 +44,7 @@ pub enum Stmt {
         body: Vec<Stmt>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Declaration")]
@@ -48,6 +53,7 @@ pub enum Stmt {
         expr: Box<Expr>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::If")]
@@ -57,6 +63,7 @@ pub enum Stmt {
         r#else_body: Option<Box<Stmt>>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Loop")]
@@ -66,6 +73,7 @@ pub enum Stmt {
         post: Option<Box<Stmt>>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
     #[serde(rename = "Stmt::Return")]
@@ -73,6 +81,7 @@ pub enum Stmt {
         expr: Option<Box<Expr>>,
         #[serde(skip)]
         #[derivative(PartialEq = "ignore")]
+        #[derivative(Hash = "ignore")]
         span: Span,
     },
 }
diff --git a/lykiadb-lang/src/lib.rs b/lykiadb-lang/src/lib.rs
index 7269ebe..ae9ae1b 100644
--- a/lykiadb-lang/src/lib.rs
+++ b/lykiadb-lang/src/lib.rs
@@ -1,6 +1,7 @@
 use std::{
     fmt::{Display, Formatter, Result},
     sync::Arc,
+    hash::Hash
 };
 
 use ast::expr::Expr;
@@ -15,7 +16,7 @@ pub mod tokenizer;
 pub type Scopes = Vec<FxHashMap<String, bool>>;
 pub type Locals = FxHashMap<usize, usize>;
 
-#[derive(Default, Debug, Copy, Clone, Eq, PartialEq, Serialize, Deserialize)]
+#[derive(Default, Debug, Copy, Clone, Eq, PartialEq, Serialize, Deserialize, Hash)]
 pub struct Span {
     pub start: usize,
     pub end: usize,
@@ -65,16 +66,33 @@ impl Literal {
     }
 }
 
+impl Hash for Literal {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        match self {
+            Literal::Str(s) => s.hash(state),
+            Literal::Num(n) => n.to_bits().hash(state),
+            Literal::Bool(b) => b.hash(state),
+            Literal::Object(o) => (o as *const _ as usize).hash(state),
+            Literal::Array(a) => a.hash(state),
+            //
+            Literal::Undefined => "undefined".hash(state),
+            Literal::NaN => "NaN".hash(state),
+            Literal::Null => "null".hash(state),
+        }
+    }
+}
+
 impl Eq for Literal {}
 
 #[derive(Debug, Clone, Serialize, Deserialize, Derivative)]
 #[serde(tag = "@type")]
-#[derivative(Eq, PartialEq)]
+#[derivative(Eq, PartialEq, Hash)]
 pub struct Identifier {
     pub name: String,
     pub dollar: bool,
     #[serde(skip)]
     #[derivative(PartialEq = "ignore")]
+    #[derivative(Hash = "ignore")]
     pub span: Span,
 }
 
diff --git a/lykiadb-lang/tests/lang/generic/expr.rs b/lykiadb-lang/tests/lang/generic/expr.rs
index d6aec15..0aaa851 100644
--- a/lykiadb-lang/tests/lang/generic/expr.rs
+++ b/lykiadb-lang/tests/lang/generic/expr.rs
@@ -1,3 +1,5 @@
+use std::collections::HashSet;
+
 use lykiadb_lang::{ast::expr::Expr, Literal, Span};
 
 fn create_simple_add_expr(id: usize, left: f64, right: f64) -> Expr {
@@ -27,6 +29,13 @@ fn identical_exprs_should_be_equal_when_ids_are_different() {
     let e1 = create_simple_add_expr(1, 1.0, 2.0);
 
     assert_eq!(e0, e1);
+
+    let mut set: HashSet<Expr> = HashSet::new();
+
+    set.insert(e0);
+
+    assert!(set.contains(&e1));
+
 }