Fix string parameters losing apostrophes when interpolated into SQL

NEXT_CHANGELOG.md

@@ -25,6 +25,14 @@
 
 - Improved SEA connection-failure error messages.
 
+- Fixed string parameters silently losing apostrophes when `supportManyParameters=1` interpolates them into SQL.
+  `SQLInterpolator` escaped `'` as the SQL-standard `''`, which Databricks does not implement: `'O''Brien'` is read
+  as the adjacent literals `'O'` and `'Brien'` and concatenated, so `O'Brien` was stored as `OBrien`. Quotes are now
+  escaped as `\'`, consistent with the backslash escaping already applied to `\`, `\n`, `\r` and `\t`.
+  Data written through this path before the upgrade still holds the stripped values, so lookups that now send the
+  apostrophe (`WHERE name = ?` bound to `O'Brien`) no longer match those rows. Only values written with
+  `supportManyParameters=1` are affected; correcting them requires a data fix.
+
 - Fixed `NullPointerException` being thrown when materializing an array containing nested object types (other arrays, structs or maps) as `DatabricksArray` when some or all elements are literal `null`. 
 ---
 *Note: When making changes, please add your change under the appropriate section

src/main/java/com/databricks/jdbc/common/util/SQLInterpolator.java

@@ -22,8 +22,8 @@ protected static String escapeInputs(String input) {
       i += Character.charCount(codePoint);
       switch (codePoint) {
         case '\'':
-          out.append("''");
-          break; // SQL-standard quote escape
+          out.append("\\'");
+          break; // Databricks escapes a quote as \', not as the SQL-standard ''
         case '\\':
           out.append("\\\\");
           break; // escape backslash

src/test/java/com/databricks/jdbc/common/util/SQLInterpolatorTest.java

@@ -80,7 +80,7 @@ public void testEscapedValues() throws DatabricksValidationException {
     Map<Integer, ImmutableSqlParameter> params = new HashMap<>();
     params.put(1, getSqlParam(1, "O'Reilly", DatabricksTypeUtil.STRING));
     params.put(2, getSqlParam(2, 200, DatabricksTypeUtil.INT));
-    String expected = "UPDATE products SET price = 'O''Reilly' WHERE id = 200";
+    String expected = "UPDATE products SET price = 'O\\'Reilly' WHERE id = 200";
     assertEquals(expected, SQLInterpolator.interpolateSQL(sql, params));
   }
 
@@ -108,7 +108,7 @@ public void testBinaryTypeEscapesMaliciousHexLookalike() throws DatabricksValida
     String sql = "SELECT ?";
     Map<Integer, ImmutableSqlParameter> params = new HashMap<>();
     params.put(1, getSqlParam(1, "X'41' OR 1=1 --", DatabricksTypeUtil.BINARY));
-    assertEquals("SELECT 'X''41'' OR 1=1 --'", SQLInterpolator.interpolateSQL(sql, params));
+    assertEquals("SELECT 'X\\'41\\' OR 1=1 --'", SQLInterpolator.interpolateSQL(sql, params));
   }
 
   @Test
@@ -217,8 +217,12 @@ public void testInterpolatePlaceholderAtStartAndEnd() throws DatabricksValidatio
 
   @Test
   public void testEscapeInputs() {
-    // Simple apostrophe doubling
-    assertEquals("'foo''bar'", SQLInterpolator.escapeInputs("foo'bar"));
+    // Apostrophe escaped with a backslash; '' would be read as two adjacent literals
+    assertEquals("'foo\\'bar'", SQLInterpolator.escapeInputs("foo'bar"));
+    // Leading, trailing and consecutive apostrophes
+    assertEquals("'\\'lead'", SQLInterpolator.escapeInputs("'lead"));
+    assertEquals("'trail\\''", SQLInterpolator.escapeInputs("trail'"));
+    assertEquals("'a\\'\\'b'", SQLInterpolator.escapeInputs("a''b"));
     // Escaping newlines
     assertEquals("'line1\\nline2'", SQLInterpolator.escapeInputs("line1\nline2"));
     // Escaping backslashes