Allow case sensitive regex operation

lib/mysql.js

@@ -529,16 +529,23 @@ MySQL.prototype.ping = function(cb) {
 MySQL.prototype.buildExpression = function(columnName, operator, operatorValue,
     propertyDefinition) {
   if (operator === 'regexp') {
+    var clause = columnName + ' REGEXP ?';
+    // By default, MySQL regexp is not case sensitive. (https://dev.mysql.com/doc/refman/5.7/en/regexp.html)
+    // To allow case sensitive regexp query, it has to be binded to a `BINARY` type.
+    // If ignore case is not specified, search it as case sensitive.
+    if (!operatorValue.ignoreCase) {
+      clause = columnName + ' REGEXP BINARY ?';
+    }
+
     if (operatorValue.ignoreCase)
       g.warn('{{MySQL}} {{regex}} syntax does not respect the {{`i`}} flag');
-
     if (operatorValue.global)
       g.warn('{{MySQL}} {{regex}} syntax does not respect the {{`g`}} flag');
 
     if (operatorValue.multiline)
       g.warn('{{MySQL}} {{regex}} syntax does not respect the {{`m`}} flag');
 
-    return new ParameterizedSQL(columnName + ' REGEXP ?',
+    return new ParameterizedSQL(clause,
         [operatorValue.source]);
   }
 

test/mysql.test.js

@@ -633,6 +633,15 @@ describe('mysql', function() {
               });
             });
       });
+
+      it('filter with case sensitive regex string', function(done) {
+        Post.find({where: {content: {regexp: '^a'}}}, function(err, posts) {
+          should.not.exist(err);
+          should.exist(posts);
+          posts.length.should.equal(0);
+          done();
+        });
+      });
     });
 
     context('with regex literals', function() {
@@ -688,6 +697,16 @@ describe('mysql', function() {
               });
             });
       });
+
+      it('filter with case sensitive regex literal', function(done) {
+        Post.find({where: {content: {regexp: /^B/}}}, function(err, posts) {
+          should.not.exist(err);
+          should.exist(posts);
+          posts.length.should.equal(1);
+          posts[0].content.should.equal('BBB');
+          done();
+        });
+      });
     });
 
     context('with regex objects', function() {
@@ -746,6 +765,15 @@ describe('mysql', function() {
                 done();
               });
             });
+
+        it('filter with case sensitive regex object', function(done) {
+          Post.find({where: {content: {regexp: new RegExp(/^a/)}}}, function(err, posts) {
+            should.not.exist(err);
+            should.exist(posts);
+            posts.length.should.equal(0);
+            done();
+          });
+        });
       });
     });
   });