diff --git a/Cargo.toml b/Cargo.toml
index 15376f2c..0cc52a2b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,6 +20,7 @@ path = "src/lib.rs"
 
 [dependencies]
 log = "0.4.5"
+ordered-float = "1.0.2"
 
 [dev-dependencies]
 simple_logger = "1.0.1"
diff --git a/src/sqlast/ddl.rs b/src/sqlast/ddl.rs
index 86bb1567..38cd5adf 100644
--- a/src/sqlast/ddl.rs
+++ b/src/sqlast/ddl.rs
@@ -3,7 +3,7 @@
 use super::{ASTNode, SQLIdent, SQLObjectName};
 
 /// An `ALTER TABLE` (`SQLStatement::SQLAlterTable`) operation
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum AlterTableOperation {
     /// `ADD <table_constraint>`
     AddConstraint(TableConstraint),
@@ -22,7 +22,7 @@ impl ToString for AlterTableOperation {
 
 /// A table-level constraint, specified in a `CREATE TABLE` or an
 /// `ALTER TABLE ADD <constraint>` statement.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum TableConstraint {
     /// `[ CONSTRAINT <name> ] { PRIMARY KEY | UNIQUE } (<columns>)`
     Unique {
diff --git a/src/sqlast/mod.rs b/src/sqlast/mod.rs
index 4dec12d7..467eac68 100644
--- a/src/sqlast/mod.rs
+++ b/src/sqlast/mod.rs
@@ -46,7 +46,7 @@ pub type SQLIdent = String;
 /// The parser does not distinguish between expressions of different types
 /// (e.g. boolean vs string), so the caller must handle expressions of
 /// inappropriate type, like `WHERE 1` or `SELECT 1=1`, as necessary.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum ASTNode {
     /// Identifier e.g. table name or column name
     SQLIdentifier(SQLIdent),
@@ -218,7 +218,7 @@ impl ToString for ASTNode {
 }
 
 /// A window specification (i.e. `OVER (PARTITION BY .. ORDER BY .. etc.)`)
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLWindowSpec {
     pub partition_by: Vec<ASTNode>,
     pub order_by: Vec<SQLOrderByExpr>,
@@ -262,7 +262,7 @@ impl ToString for SQLWindowSpec {
 
 /// Specifies the data processed by a window function, e.g.
 /// `RANGE UNBOUNDED PRECEDING` or `ROWS BETWEEN 5 PRECEDING AND CURRENT ROW`.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLWindowFrame {
     pub units: SQLWindowFrameUnits,
     pub start_bound: SQLWindowFrameBound,
@@ -271,7 +271,7 @@ pub struct SQLWindowFrame {
     // TBD: EXCLUDE
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLWindowFrameUnits {
     Rows,
     Range,
@@ -304,7 +304,7 @@ impl FromStr for SQLWindowFrameUnits {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLWindowFrameBound {
     /// "CURRENT ROW"
     CurrentRow,
@@ -329,7 +329,7 @@ impl ToString for SQLWindowFrameBound {
 
 /// A top-level statement (SELECT, INSERT, CREATE, etc.)
 #[allow(clippy::large_enum_variant)]
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLStatement {
     /// SELECT
     SQLQuery(Box<SQLQuery>),
@@ -531,7 +531,7 @@ impl ToString for SQLStatement {
 }
 
 /// A name of a table, view, custom type, etc., possibly multi-part, i.e. db.schema.obj
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLObjectName(pub Vec<SQLIdent>);
 
 impl ToString for SQLObjectName {
@@ -541,7 +541,7 @@ impl ToString for SQLObjectName {
 }
 
 /// SQL assignment `foo = expr` as used in SQLUpdate
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLAssignment {
     id: SQLIdent,
     value: ASTNode,
@@ -554,7 +554,7 @@ impl ToString for SQLAssignment {
 }
 
 /// SQL column definition
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLColumnDef {
     pub name: SQLIdent,
     pub data_type: SQLType,
@@ -584,7 +584,7 @@ impl ToString for SQLColumnDef {
 }
 
 /// SQL function
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLFunction {
     pub name: SQLObjectName,
     pub args: Vec<ASTNode>,
@@ -609,7 +609,7 @@ impl ToString for SQLFunction {
 }
 
 /// External table's available file format
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum FileFormat {
     TEXTFILE,
     SEQUENCEFILE,
@@ -658,7 +658,7 @@ impl FromStr for FileFormat {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLObjectType {
     Table,
     View,
diff --git a/src/sqlast/query.rs b/src/sqlast/query.rs
index 297d6e51..3b16cd4c 100644
--- a/src/sqlast/query.rs
+++ b/src/sqlast/query.rs
@@ -2,7 +2,7 @@ use super::*;
 
 /// The most complete variant of a `SELECT` query expression, optionally
 /// including `WITH`, `UNION` / other set operations, and `ORDER BY`.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLQuery {
     /// WITH (common table expressions, or CTEs)
     pub ctes: Vec<Cte>,
@@ -44,7 +44,7 @@ impl ToString for SQLQuery {
 
 /// A node in a tree, representing a "query body" expression, roughly:
 /// `SELECT ... [ {UNION|EXCEPT|INTERSECT} SELECT ...]`
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLSetExpr {
     /// Restricted SELECT .. FROM .. HAVING (no ORDER BY or set operations)
     Select(Box<SQLSelect>),
@@ -85,7 +85,7 @@ impl ToString for SQLSetExpr {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLSetOperator {
     Union,
     Except,
@@ -105,7 +105,7 @@ impl ToString for SQLSetOperator {
 /// A restricted variant of `SELECT` (without CTEs/`ORDER BY`), which may
 /// appear either as the only body item of an `SQLQuery`, or as an operand
 /// to a set operation like `UNION`.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLSelect {
     pub distinct: bool,
     /// projection expressions
@@ -152,7 +152,7 @@ impl ToString for SQLSelect {
 /// The names in the column list before `AS`, when specified, replace the names
 /// of the columns returned by the query. The parser does not validate that the
 /// number of columns in the query matches the number of columns in the query.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct Cte {
     pub alias: SQLIdent,
     pub query: SQLQuery,
@@ -170,7 +170,7 @@ impl ToString for Cte {
 }
 
 /// One item of the comma-separated list following `SELECT`
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLSelectItem {
     /// Any expression, not followed by `[ AS ] alias`
     UnnamedExpression(ASTNode),
@@ -196,7 +196,7 @@ impl ToString for SQLSelectItem {
 }
 
 /// A table name or a parenthesized subquery with an optional alias
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum TableFactor {
     Table {
         name: SQLObjectName,
@@ -255,7 +255,7 @@ impl ToString for TableFactor {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct Join {
     pub relation: TableFactor,
     pub join_operator: JoinOperator,
@@ -307,7 +307,7 @@ impl ToString for Join {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum JoinOperator {
     Inner(JoinConstraint),
     LeftOuter(JoinConstraint),
@@ -317,7 +317,7 @@ pub enum JoinOperator {
     Cross,
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum JoinConstraint {
     On(ASTNode),
     Using(Vec<SQLIdent>),
@@ -325,7 +325,7 @@ pub enum JoinConstraint {
 }
 
 /// SQL ORDER BY expression
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct SQLOrderByExpr {
     pub expr: ASTNode,
     pub asc: Option<bool>,
@@ -341,7 +341,7 @@ impl ToString for SQLOrderByExpr {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub struct Fetch {
     pub with_ties: bool,
     pub percent: bool,
diff --git a/src/sqlast/sql_operator.rs b/src/sqlast/sql_operator.rs
index 9cd14fd0..173bc80d 100644
--- a/src/sqlast/sql_operator.rs
+++ b/src/sqlast/sql_operator.rs
@@ -1,5 +1,5 @@
 /// SQL Operator
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLOperator {
     Plus,
     Minus,
diff --git a/src/sqlast/sqltype.rs b/src/sqlast/sqltype.rs
index 880a6aa4..ba339d07 100644
--- a/src/sqlast/sqltype.rs
+++ b/src/sqlast/sqltype.rs
@@ -1,7 +1,7 @@
 use super::SQLObjectName;
 
 /// SQL data types
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum SQLType {
     /// Fixed-length character type e.g. CHAR(10)
     Char(Option<u64>),
diff --git a/src/sqlast/value.rs b/src/sqlast/value.rs
index 0cb7fab4..3c52e434 100644
--- a/src/sqlast/value.rs
+++ b/src/sqlast/value.rs
@@ -1,10 +1,12 @@
+use ordered_float::OrderedFloat;
+
 /// Primitive SQL values such as number and string
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Hash)]
 pub enum Value {
     /// Unsigned integer value
     Long(u64),
     /// Unsigned floating point value
-    Double(f64),
+    Double(OrderedFloat<f64>),
     /// 'string value'
     SingleQuotedString(String),
     /// N'string value'
diff --git a/src/sqlparser.rs b/src/sqlparser.rs
index 330b10b0..6057b14e 100644
--- a/src/sqlparser.rs
+++ b/src/sqlparser.rs
@@ -1031,7 +1031,7 @@ impl Parser {
                     }
                 },
                 Token::Number(ref n) if n.contains('.') => match n.parse::<f64>() {
-                    Ok(n) => Ok(Value::Double(n)),
+                    Ok(n) => Ok(Value::Double(n.into())),
                     Err(e) => parser_err!(format!("Could not parse '{}' as f64: {}", n, e)),
                 },
                 Token::Number(ref n) => match n.parse::<u64>() {