From 80dccf68856ef9ad019b25e86d0e2872b516c40c Mon Sep 17 00:00:00 2001
From: Justin Haug <penguinsoccer@outlook.com>
Date: Mon, 22 Apr 2019 13:32:05 -0400
Subject: [PATCH] Add support for escaping single quote strings

---
 src/sqlast/value.rs        | 14 +++++++++++++-
 src/sqltokenizer.rs        | 10 +++++++++-
 tests/sqlparser_generic.rs | 17 +++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/sqlast/value.rs b/src/sqlast/value.rs
index a061080a..eedb14a9 100644
--- a/src/sqlast/value.rs
+++ b/src/sqlast/value.rs
@@ -35,7 +35,7 @@ impl ToString for Value {
             Value::Long(v) => v.to_string(),
             Value::Double(v) => v.to_string(),
             Value::Uuid(v) => v.to_string(),
-            Value::SingleQuotedString(v) => format!("'{}'", v),
+            Value::SingleQuotedString(v) => format!("'{}'", escape_single_quote_string(v)),
             Value::NationalStringLiteral(v) => format!("N'{}'", v),
             Value::Boolean(v) => v.to_string(),
             Value::Date(v) => v.to_string(),
@@ -46,3 +46,15 @@ impl ToString for Value {
         }
     }
 }
+
+fn escape_single_quote_string(s: &str) -> String {
+    let mut escaped = String::new();
+    for c in s.chars() {
+        if c == '\'' {
+            escaped.push_str("\'\'");
+        } else {
+            escaped.push(c);
+        }
+    }
+    escaped
+}
diff --git a/src/sqltokenizer.rs b/src/sqltokenizer.rs
index 83105736..8735627d 100644
--- a/src/sqltokenizer.rs
+++ b/src/sqltokenizer.rs
@@ -462,7 +462,15 @@ impl<'a> Tokenizer<'a> {
             match ch {
                 '\'' => {
                     chars.next(); // consume
-                    break;
+                    let escaped_quote = chars.peek()
+                        .map(|c| *c == '\'')
+                        .unwrap_or(false);
+                    if escaped_quote {
+                        s.push('\'');
+                        chars.next();
+                    } else {
+                        break;
+                    }
                 }
                 _ => {
                     chars.next(); // consume
diff --git a/tests/sqlparser_generic.rs b/tests/sqlparser_generic.rs
index ea60e6d4..647a9338 100644
--- a/tests/sqlparser_generic.rs
+++ b/tests/sqlparser_generic.rs
@@ -148,6 +148,23 @@ fn parse_projection_nested_type() {
     //TODO: add assertions
 }
 
+#[test]
+fn parse_escaped_single_quote_string_predicate() {
+    use self::ASTNode::*;
+    use self::SQLOperator::*;
+    let sql = "SELECT id, fname, lname FROM customer \
+               WHERE salary != 'Jim''s salary'";
+    let ast = verified_only_select(sql);
+    assert_eq!(
+        Some(SQLBinaryExpr {
+            left: Box::new(SQLIdentifier("salary".to_string())),
+            op: NotEq,
+            right: Box::new(SQLValue(Value::SingleQuotedString("Jim's salary".to_string())))
+        }),
+        ast.selection,
+    );
+}
+
 #[test]
 fn parse_compound_expr_1() {
     use self::ASTNode::*;