diff --git a/src/index.ts b/src/index.ts
index 3cee1fa..b495664 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -34,6 +34,8 @@ const charCode = {
   dash: 45,
   slash: 47,
   asterisk: 42,
+  exclamation: 33,
+  plus: 43,
   questionMark: 63,
   newline: 10,
   space: 32,
@@ -129,11 +131,22 @@ const skipSqlContext = (sql: string, position: number): number => {
   }
 
   if (currentChar === charCode.dash && nextChar === charCode.dash) {
-    const lineBreak = sql.indexOf('\n', position + 2);
-    return lineBreak === -1 ? sql.length : lineBreak + 1;
+    const afterDash = sql.charCodeAt(position + 2);
+
+    if (Number.isNaN(afterDash) || afterDash <= charCode.space) {
+      const lineBreak = sql.indexOf('\n', position + 2);
+      return lineBreak === -1 ? sql.length : lineBreak + 1;
+    }
+
+    return -1;
   }
 
   if (currentChar === charCode.slash && nextChar === charCode.asterisk) {
+    const markerChar = sql.charCodeAt(position + 2);
+
+    if (markerChar === charCode.exclamation || markerChar === charCode.plus)
+      return -1;
+
     const commentEnd = sql.indexOf('*/', position + 2);
     return commentEnd === -1 ? sql.length : commentEnd + 2;
   }
diff --git a/test/delimiters.test.ts b/test/delimiters.test.ts
index 3488b97..c337018 100644
--- a/test/delimiters.test.ts
+++ b/test/delimiters.test.ts
@@ -338,6 +338,21 @@ describe('Query comments for debugging', () => {
       "SELECT * FROM users -- get all users\nWHERE status = 'active'"
     );
   });
+
+  test('double dash without trailing whitespace is not a comment', () => {
+    const sql = format('SELECT 1--2, ?', ['VAL']);
+    assert.equal(sql, "SELECT 1--2, 'VAL'");
+  });
+
+  test('executable comment placeholder is substituted, not skipped', () => {
+    const sql = format('SELECT /*!40101 ? */ , ?', ['A', 'B']);
+    assert.equal(sql, "SELECT /*!40101 'A' */ , 'B'");
+  });
+
+  test('optimizer hint placeholder is substituted, not skipped', () => {
+    const sql = format('SELECT /*+ MAX_EXECUTION_TIME(?) */ id FROM t', [1000]);
+    assert.equal(sql, 'SELECT /*+ MAX_EXECUTION_TIME(1000) */ id FROM t');
+  });
 });
 
 describe('Real edge cases', () => {