Expose structured ORDER BY fragment parsing

Author: minleejae

src/main/java/net/sf/jsqlparser/parser/CCJSqlParserUtil.java

@@ -13,6 +13,8 @@
 import java.io.InputStream;
 import java.io.Reader;
 import java.util.Stack;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -31,6 +33,7 @@
 import net.sf.jsqlparser.statement.Statement;
 import net.sf.jsqlparser.statement.Statements;
 import net.sf.jsqlparser.statement.create.table.ColDataType;
+import net.sf.jsqlparser.statement.select.OrderByElement;
 
 /**
  * Toolfunctions to start and use JSqlParser.
@@ -242,34 +245,68 @@ public static ColDataType parseColDataType(String columnDataType) throws JSQLPar
      */
     public static ColDataType parseColDataType(String columnDataType,
             Consumer<CCJSqlParser> consumer) throws JSQLParserException {
-        if (columnDataType == null || columnDataType.isEmpty()) {
+        return parseFragment(columnDataType, "column data type", consumer,
+                CCJSqlParser::ColDataType);
+    }
+
+    /**
+     * Parses comma-separated ORDER BY elements without the ORDER BY keywords. Trailing tokens are
+     * rejected. Returns an empty list for null or empty input.
+     */
+    public static List<OrderByElement> parseOrderByElements(String elements)
+            throws JSQLParserException {
+        return parseOrderByElements(elements, null);
+    }
+
+    /**
+     * Parses ORDER BY elements with optional parser configuration. The input contains only the
+     * elements (for example, {@code name DESC, id ASC}), and must be consumed completely.
+     *
+     * @return the parsed elements, or an empty list for null or empty input
+     * @throws JSQLParserException when the input cannot be parsed completely
+     */
+    public static List<OrderByElement> parseOrderByElements(String elements,
+            Consumer<CCJSqlParser> consumer) throws JSQLParserException {
+        return elements == null || elements.isEmpty() ? new ArrayList<>()
+                : parseFragment(elements, "ORDER BY elements", consumer,
+                        CCJSqlParser::OrderByElementList);
+    }
+
+    @FunctionalInterface
+    private interface FragmentParser<T> {
+        T parse(CCJSqlParser parser) throws ParseException;
+    }
+
+    private static <T> T parseFragment(String input, String description,
+            Consumer<CCJSqlParser> consumer, FragmentParser<T> fragment)
+            throws JSQLParserException {
+        if (input == null || input.isEmpty()) {
             return null;
         }
-
         try {
-            return parseColDataType(columnDataType, false, consumer);
+            return parseFragment(input, description, false, consumer, fragment);
         } catch (JSQLParserException ex) {
-            return parseColDataType(columnDataType, true, consumer);
+            return parseFragment(input, description, true, consumer, fragment);
         }
     }
 
-    private static ColDataType parseColDataType(String columnDataType, boolean allowComplexParsing,
-            Consumer<CCJSqlParser> consumer) throws JSQLParserException {
-        CCJSqlParser parser = newParser(columnDataType)
-                .withAllowComplexParsing(allowComplexParsing);
+    private static <T> T parseFragment(String input, String description,
+            boolean allowComplexParsing,
+            Consumer<CCJSqlParser> consumer, FragmentParser<T> fragment)
+            throws JSQLParserException {
+        CCJSqlParser parser = newParser(input).withAllowComplexParsing(allowComplexParsing);
         if (consumer != null) {
             consumer.accept(parser);
         }
-
         try {
-            ColDataType result = parser.ColDataType();
+            T result = fragment.parse(parser);
             if (parser.getNextToken().kind != CCJSqlParserTokenManager.EOF) {
                 throw new JSQLParserException(
-                        "could only parse partial column data type " + result);
+                        "could only parse partial " + description + " " + result);
             }
             return result;
         } catch (ParseException ex) {
-            throw new JSQLParserException(columnDataType, ex);
+            throw new JSQLParserException(input, ex);
         }
     }
 

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -8122,15 +8122,23 @@ Expression Qualify():
 
 List<OrderByElement> OrderByElements():
 {
-    List<OrderByElement> orderByList = new ArrayList<OrderByElement>();
-    OrderByElement orderByElement = null;
+    List<OrderByElement> elements;
 }
 {
-    <K_ORDER> [ <K_SIBLINGS> ] <K_BY> orderByElement=OrderByElement() { orderByList.add(orderByElement); }
-        ( LOOKAHEAD(2) "," orderByElement=OrderByElement() { orderByList.add(orderByElement); } )*
-    {
-        return orderByList;
-    }
+    <K_ORDER> [ <K_SIBLINGS> ] <K_BY> elements=OrderByElementList()
+    { return elements; }
+}
+
+/** Shared element list for statement clauses and the fragment parsing API. */
+List<OrderByElement> OrderByElementList():
+{
+    List<OrderByElement> elements = new ArrayList<OrderByElement>();
+    OrderByElement element;
+}
+{
+    element=OrderByElement() { elements.add(element); }
+    ( LOOKAHEAD(2) "," element=OrderByElement() { elements.add(element); } )*
+    { return elements; }
 }
 
 OrderByElement OrderByElement():

src/test/java/net/sf/jsqlparser/parser/OrderByFragmentTest.java

@@ -0,0 +1,79 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.parser;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import java.util.List;
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.expression.LongValue;
+import net.sf.jsqlparser.expression.JdbcParameter;
+import net.sf.jsqlparser.statement.select.OrderByElement;
+import net.sf.jsqlparser.statement.select.PlainSelect;
+import net.sf.jsqlparser.util.deparser.ExpressionDeParser;
+import net.sf.jsqlparser.util.deparser.OrderByDeParser;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class OrderByFragmentTest {
+    @ParameterizedTest
+    @ValueSource(strings = {"a DESC NULLS LAST, b ASC", "COALESCE(a, 0) DESC, b + ? ASC",
+            "(1 + a) / (1 + b) DESC", "a COLLATE \"C\" ASC", "a WITH FILL FROM 1 TO 5"})
+    void usesTheSameStructuredElementsAsAnOrderByClause(String fragment) throws Exception {
+        List<OrderByElement> elements = CCJSqlParserUtil.parseOrderByElements(fragment);
+        PlainSelect select =
+                (PlainSelect) CCJSqlParserUtil.parse("SELECT * FROM t ORDER BY " + fragment);
+        assertEquals(select.getOrderByElements().toString(), elements.toString());
+        StringBuilder output = new StringBuilder();
+        new OrderByDeParser(new ExpressionDeParser(null, output), output).deParse(elements);
+        assertEquals(elements.toString(),
+                CCJSqlParserUtil
+                        .parseOrderByElements(output.toString().substring(" ORDER BY ".length()))
+                        .toString());
+    }
+
+    @Test
+    void exposesSortFlagsAndSupportsCustomExpressionRendering() throws Exception {
+        List<OrderByElement> elements =
+                CCJSqlParserUtil.parseOrderByElements("1 DESC NULLS LAST, 2 ASC");
+        assertEquals(OrderByElement.NullOrdering.NULLS_LAST, elements.get(0).getNullOrdering());
+        assertTrue(elements.get(1).isAscDescPresent());
+        StringBuilder output = new StringBuilder();
+        ExpressionDeParser expressions = new ExpressionDeParser(null, output) {
+            @Override
+            public <S> StringBuilder visit(LongValue value, S context) {
+                return getBuilder().append(value.getValue() + 100);
+            }
+        };
+        new OrderByDeParser(expressions, output).deParse(elements);
+        assertEquals(" ORDER BY 101 DESC NULLS LAST, 102 ASC", output.toString());
+    }
+
+    @Test
+    void appliesConfigurationAndStartsEachFragmentWithFreshParameterState() throws Exception {
+        assertEquals("[my column] DESC", CCJSqlParserUtil.parseOrderByElements("[my column] DESC",
+                parser -> parser.withSquareBracketQuotation(true)).get(0).toString());
+        for (int i = 0; i < 2; i++) {
+            OrderByElement element = CCJSqlParserUtil.parseOrderByElements("? DESC").get(0);
+            assertEquals(1, ((JdbcParameter) element.getExpression()).getIndex());
+        }
+        assertTrue(CCJSqlParserUtil.parseOrderByElements(null).isEmpty());
+        assertTrue(CCJSqlParserUtil.parseOrderByElements("").isEmpty());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"a DESC LIMIT 1", "a DESC,", "a DESC; SELECT 1", "ORDER BY a", "a +"})
+    void rejectsTrailingInputAndIncompleteElements(String fragment) {
+        assertThrows(JSQLParserException.class,
+                () -> CCJSqlParserUtil.parseOrderByElements(fragment));
+    }
+}