diff --git a/browser/sql-parser.js b/browser/sql-parser.js
index 4ebe726..3c7f5d6 100644
--- a/browser/sql-parser.js
+++ b/browser/sql-parser.js
@@ -55,6 +55,27 @@
       return this.tokens.push([name, value, this.currentLine]);
     };
 
+    Lexer.prototype.tokenizeFromStringRegex = function(name, regex, part, lengthPart, output) {
+      var match, partMatch;
+      if (part == null) {
+        part = 0;
+      }
+      if (lengthPart == null) {
+        lengthPart = part;
+      }
+      if (output == null) {
+        output = true;
+      }
+      if (!(match = regex.exec(this.chunk))) {
+        return 0;
+      }
+      partMatch = match[part].replace(/''/g, "'");
+      if (output) {
+        this.token(name, partMatch);
+      }
+      return match[lengthPart].length;
+    };
+
     Lexer.prototype.tokenizeFromRegex = function(name, regex, part, lengthPart, output) {
       var match, partMatch;
       if (part == null) {
@@ -169,7 +190,7 @@
     };
 
     Lexer.prototype.stringToken = function() {
-      return this.tokenizeFromRegex('STRING', STRING, 1, 0) || this.tokenizeFromRegex('DBLSTRING', DBLSTRING, 1, 0);
+      return this.tokenizeFromStringRegex('STRING', STRING, 1, 0) || this.tokenizeFromRegex('DBLSTRING', DBLSTRING, 1, 0);
     };
 
     Lexer.prototype.parensToken = function() {
@@ -221,7 +242,7 @@
 
     BOOLEAN = ['TRUE', 'FALSE', 'NULL'];
 
-    MATH = ['+', '-'];
+    MATH = ['+', '-', '||', '&&'];
 
     MATH_MULTI = ['/', '*'];
 
@@ -237,7 +258,7 @@
 
     NUMBER = /^[0-9]+(\.[0-9]+)?/;
 
-    STRING = /^'([^\\']*(?:\\.[^\\']*)*)'/;
+    STRING = /^'((?:[^\\']+?|\\.|'')*)'(?!')/;
 
     DBLSTRING = /^"([^\\"]*(?:\\.[^\\"]*)*)"/;
 
@@ -886,7 +907,9 @@ if (typeof module !== 'undefined' && require.main === module) {
     }
 
     StringValue.prototype.toString = function() {
-      return "" + this.quoteType + this.value + this.quoteType;
+      var escaped;
+      escaped = this.quoteType === "'" ? this.value.replace(/(^|[^\\])'/g, "$1''") : this.value;
+      return "" + this.quoteType + escaped + this.quoteType;
     };
 
     return StringValue;
diff --git a/lib/lexer.js b/lib/lexer.js
index 3f0ed9c..dffd850 100644
--- a/lib/lexer.js
+++ b/lib/lexer.js
@@ -50,6 +50,27 @@
       return this.tokens.push([name, value, this.currentLine]);
     };
 
+    Lexer.prototype.tokenizeFromStringRegex = function(name, regex, part, lengthPart, output) {
+      var match, partMatch;
+      if (part == null) {
+        part = 0;
+      }
+      if (lengthPart == null) {
+        lengthPart = part;
+      }
+      if (output == null) {
+        output = true;
+      }
+      if (!(match = regex.exec(this.chunk))) {
+        return 0;
+      }
+      partMatch = match[part].replace(/''/g, "'");
+      if (output) {
+        this.token(name, partMatch);
+      }
+      return match[lengthPart].length;
+    };
+
     Lexer.prototype.tokenizeFromRegex = function(name, regex, part, lengthPart, output) {
       var match, partMatch;
       if (part == null) {
@@ -164,7 +185,7 @@
     };
 
     Lexer.prototype.stringToken = function() {
-      return this.tokenizeFromRegex('STRING', STRING, 1, 0) || this.tokenizeFromRegex('DBLSTRING', DBLSTRING, 1, 0);
+      return this.tokenizeFromStringRegex('STRING', STRING, 1, 0) || this.tokenizeFromRegex('DBLSTRING', DBLSTRING, 1, 0);
     };
 
     Lexer.prototype.parensToken = function() {
@@ -216,7 +237,7 @@
 
     BOOLEAN = ['TRUE', 'FALSE', 'NULL'];
 
-    MATH = ['+', '-'];
+    MATH = ['+', '-', '||', '&&'];
 
     MATH_MULTI = ['/', '*'];
 
@@ -232,7 +253,7 @@
 
     NUMBER = /^[0-9]+(\.[0-9]+)?/;
 
-    STRING = /^'([^\\']*(?:\\.[^\\']*)*)'/;
+    STRING = /^'((?:[^\\']+?|\\.|'')*)'(?!')/;
 
     DBLSTRING = /^"([^\\"]*(?:\\.[^\\"]*)*)"/;
 
diff --git a/lib/nodes.js b/lib/nodes.js
index 6bb9bb9..b93ace6 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -154,7 +154,9 @@
     }
 
     StringValue.prototype.toString = function() {
-      return "" + this.quoteType + this.value + this.quoteType;
+      var escaped;
+      escaped = this.quoteType === "'" ? this.value.replace(/(^|[^\\])'/g, "$1''") : this.value;
+      return "" + this.quoteType + escaped + this.quoteType;
     };
 
     return StringValue;
diff --git a/src/lexer.coffee b/src/lexer.coffee
index 4cb3d8b..249aa91 100644
--- a/src/lexer.coffee
+++ b/src/lexer.coffee
@@ -41,6 +41,12 @@ class Lexer
   token: (name, value) ->
     @tokens.push([name, value, @currentLine])
 
+  tokenizeFromStringRegex: (name, regex, part=0, lengthPart=part, output=true) ->
+    return 0 unless match = regex.exec(@chunk)
+    partMatch = match[part].replace(/''/g, "'")
+    @token(name, partMatch) if output
+    return match[lengthPart].length
+
   tokenizeFromRegex: (name, regex, part=0, lengthPart=part, output=true) ->
     return 0 unless match = regex.exec(@chunk)
     partMatch = match[part]
@@ -112,7 +118,7 @@ class Lexer
   numberToken:      -> @tokenizeFromRegex('NUMBER', NUMBER)
   parameterToken:   -> @tokenizeFromRegex('PARAMETER', PARAMETER)
   stringToken:      ->
-    @tokenizeFromRegex('STRING', STRING, 1, 0) ||
+    @tokenizeFromStringRegex('STRING', STRING, 1, 0) ||
     @tokenizeFromRegex('DBLSTRING', DBLSTRING, 1, 0)
 
 
@@ -146,7 +152,7 @@ class Lexer
   SQL_CONDITIONALS    = ['AND', 'OR']
   SQL_BETWEENS        = ['BETWEEN', 'NOT BETWEEN']
   BOOLEAN             = ['TRUE', 'FALSE', 'NULL']
-  MATH                = ['+', '-']
+  MATH                = ['+', '-', '||', '&&']
   MATH_MULTI          = ['/', '*']
   STAR                = /^\*/
   SEPARATOR           = /^,/
@@ -154,7 +160,7 @@ class Lexer
   LITERAL             = /^`?([a-z_][a-z0-9_]{0,})`?/i
   PARAMETER           = /^\$[0-9]+/
   NUMBER              = /^[0-9]+(\.[0-9]+)?/
-  STRING              = /^'([^\\']*(?:\\.[^\\']*)*)'/
+  STRING              = /^'((?:[^\\']+?|\\.|'')*)'(?!')/
   DBLSTRING           = /^"([^\\"]*(?:\\.[^\\"]*)*)"/
 
 
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 119fd43..f5f7eb1 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -55,7 +55,9 @@ exports.LiteralValue = class LiteralValue
 
 exports.StringValue = class StringValue
   constructor: (@value, @quoteType="''") -> null
-  toString: -> "#{@quoteType}#{@value}#{@quoteType}"
+  toString: ->
+    escaped = if @quoteType is "'" then @value.replace /(^|[^\\])'/g, "$1''" else @value
+    "#{@quoteType}#{escaped}#{@quoteType}"
 
 exports.NumberValue = class LiteralValue
   constructor: (value) -> @value = Number(value)
diff --git a/test/grammar.spec.coffee b/test/grammar.spec.coffee
index c681f7c..b51ed5f 100644
--- a/test/grammar.spec.coffee
+++ b/test/grammar.spec.coffee
@@ -292,6 +292,13 @@ describe "SQL Grammar", ->
         WHERE (`foo` = 'I\\'m')
       """
 
+    it "parses single quote", ->
+      parse("select * from a where foo = ''''").toString().should.eql """
+      SELECT *
+        FROM `a`
+        WHERE (`foo` = '''')
+      """
+
     it "allows using double quotes", ->
       parse('select * from a where foo = "a"').toString().should.eql """
       SELECT *
@@ -299,6 +306,13 @@ describe "SQL Grammar", ->
         WHERE (`foo` = "a")
       """
 
+    it "allows using two single quotes", ->
+      parse("select * from a where foo = 'I''m'").toString().should.eql """
+      SELECT *
+        FROM `a`
+        WHERE (`foo` = 'I''m')
+      """
+
     it "allows nesting different quote styles", ->
       parse("""select * from a where foo = "I'm" """).toString().should.eql """
       SELECT *