diff --git a/lib/src/sql/datetime.rs b/lib/src/sql/datetime.rs
index ed3e4a0e..4f02ac21 100644
--- a/lib/src/sql/datetime.rs
+++ b/lib/src/sql/datetime.rs
@@ -11,6 +11,9 @@ use std::fmt;
 use std::ops::Deref;
 use std::str;
 
+const SINGLE: char = '\'';
+const DOUBLE: char = '"';
+
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Deserialize)]
 pub struct Datetime(pub DateTime<Utc>);
 
@@ -69,12 +72,12 @@ impl Serialize for Datetime {
 
 pub fn datetime(i: &str) -> IResult<&str, Datetime> {
 	alt((
-		delimited(char('\"'), datetime_raw, char('\"')),
-		delimited(char('\''), datetime_raw, char('\'')),
+		delimited(char(DOUBLE), datetime_raw, char(DOUBLE)),
+		delimited(char(SINGLE), datetime_raw, char(SINGLE)),
 	))(i)
 }
 
-pub fn datetime_raw(i: &str) -> IResult<&str, Datetime> {
+fn datetime_raw(i: &str) -> IResult<&str, Datetime> {
 	alt((nano, time, date))(i)
 }
 
diff --git a/lib/src/sql/duration.rs b/lib/src/sql/duration.rs
index 99fb842a..0525f69c 100644
--- a/lib/src/sql/duration.rs
+++ b/lib/src/sql/duration.rs
@@ -203,7 +203,7 @@ pub fn duration(i: &str) -> IResult<&str, Duration> {
 	Ok((i, v.iter().sum::<Duration>()))
 }
 
-pub fn duration_raw(i: &str) -> IResult<&str, Duration> {
+fn duration_raw(i: &str) -> IResult<&str, Duration> {
 	let (i, v) = part(i)?;
 	let (i, u) = unit(i)?;
 	Ok((
diff --git a/lib/src/sql/script.rs b/lib/src/sql/script.rs
index b47b7d82..452b7c6e 100644
--- a/lib/src/sql/script.rs
+++ b/lib/src/sql/script.rs
@@ -56,7 +56,7 @@ pub fn script(i: &str) -> IResult<&str, Script> {
 	Ok((i, Script(String::from(v))))
 }
 
-pub fn script_raw(i: &str) -> IResult<&str, &str> {
+fn script_raw(i: &str) -> IResult<&str, &str> {
 	recognize(many1(alt((char_any, char_object, string_single, string_double, string_backtick))))(i)
 }