fix: keep all clauses when deparsing SELECT without FROM (#2483)

PlainSelect.appendTo printed the post-FROM clause chain (oracle
hierarchical, PREFERRING, GROUP BY, HAVING, QUALIFY, WINDOW, EMIT
CHANGES) only when a FROM item was present; the "without from"
branch rendered WHERE and PREWHERE alone. Move the shared clause
chain out of the fromItem branch, mirroring SelectDeParser, so a
FROM-less SELECT renders every clause stored on the AST. Output
for SELECTs with FROM is unchanged (same checks in the same order).

Signed-off-by: 付典 <fudianchn@gmail.com>

Author: fudianchn

src/main/java/net/sf/jsqlparser/statement/select/PlainSelect.java

@@ -607,43 +607,35 @@ public StringBuilder appendSelectBodyTo(StringBuilder builder) {
             if (ksqlWindow != null) {
                 builder.append(" WINDOW ").append(ksqlWindow);
             }
-            if (preWhere != null) {
-                builder.append(" PREWHERE ").append(preWhere);
-            }
-            if (where != null) {
-                builder.append(" WHERE ").append(where);
-            }
-            if (oracleHierarchical != null) {
-                builder.append(oracleHierarchical);
-            }
-            if (preferringClause != null) {
-                builder.append(" ").append(preferringClause);
-            }
-            if (groupBy != null) {
-                builder.append(" ").append(groupBy);
-            }
-            if (having != null) {
-                builder.append(" HAVING ").append(having);
-            }
-            if (qualify != null) {
-                builder.append(" QUALIFY ").append(qualify);
-            }
-            if (windowDefinitions != null) {
-                builder.append(" WINDOW ");
-                builder.append(windowDefinitions.stream().map(WindowDefinition::toString)
-                        .collect(joining(", ")));
-            }
-            if (emitChanges) {
-                builder.append(" EMIT CHANGES");
-            }
-        } else {
-            // without from
-            if (preWhere != null) {
-                builder.append(" PREWHERE ").append(preWhere);
-            }
-            if (where != null) {
-                builder.append(" WHERE ").append(where);
-            }
+        }
+        if (preWhere != null) {
+            builder.append(" PREWHERE ").append(preWhere);
+        }
+        if (where != null) {
+            builder.append(" WHERE ").append(where);
+        }
+        if (oracleHierarchical != null) {
+            builder.append(oracleHierarchical);
+        }
+        if (preferringClause != null) {
+            builder.append(" ").append(preferringClause);
+        }
+        if (groupBy != null) {
+            builder.append(" ").append(groupBy);
+        }
+        if (having != null) {
+            builder.append(" HAVING ").append(having);
+        }
+        if (qualify != null) {
+            builder.append(" QUALIFY ").append(qualify);
+        }
+        if (windowDefinitions != null) {
+            builder.append(" WINDOW ");
+            builder.append(windowDefinitions.stream().map(WindowDefinition::toString)
+                    .collect(joining(", ")));
+        }
+        if (emitChanges) {
+            builder.append(" EMIT CHANGES");
         }
         if (intoTempTable != null) {
             builder.append(" INTO TEMP ").append(intoTempTable);

src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java

@@ -1907,6 +1907,29 @@ public void testSelectFunction() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed(statement);
     }
 
+    @Test
+    public void testSelectWithoutFromRetainsWhereGroupByHaving() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT 1 WHERE 1 = 1");
+        PlainSelect plainSelect =
+                (PlainSelect) assertSqlCanBeParsedAndDeparsed("SELECT 1 GROUP BY 1 HAVING 1 = 1");
+        assertNotNull(plainSelect.getGroupBy());
+        assertNotNull(plainSelect.getHaving());
+    }
+
+    @Test
+    public void testSelectWithoutFromRetainsWindowAndQualify() throws JSQLParserException {
+        PlainSelect plainSelect =
+                (PlainSelect) assertSqlCanBeParsedAndDeparsed("SELECT 1 WINDOW w AS (ORDER BY 1)");
+        assertEquals(1, plainSelect.getWindowDefinitions().size());
+        assertSqlCanBeParsedAndDeparsed("SELECT 1 QUALIFY 1 = 1");
+    }
+
+    @Test
+    public void testSelectWithoutFromRetainsHierarchicalAndPreferring() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT 1 START WITH 1 = 1 CONNECT BY LEVEL <= 1");
+        assertSqlCanBeParsedAndDeparsed("SELECT 1 PREFERRING HIGH 1");
+    }
+
     @Test
     public void testWeirdSelect() throws JSQLParserException {
         String sql =