[BUG] JSQLParser 5.4-SNAPSHOT : RDBMS : SELECT without FROM silently drops GROUP BY / HAVING / WINDOW / QUALIFY / CONNECT BY / PREFERRING in toString()

[fudianchn]

Failing SQL Feature:

SELECT without a FROM clause parses fine (supported Standard SQL, see #1514), but PlainSelect.toString() silently drops every clause after the select items except WHERE / PREWHERE: GROUP BY, HAVING, WINDOW, QUALIFY, START WITH / CONNECT BY and PREFERRING are all stored on the AST yet disappear from the output. A parse -> toString -> reparse round trip silently rewrites the statement.

The StatementDeParser path already renders all of them (SelectDeParser prints the whole clause chain outside its getFromItem() != null block), so the two render paths disagree.

Root cause: PlainSelect.appendSelectBodyTo (src/main/java/net/sf/jsqlparser/statement/select/PlainSelect.java): the shared clause chain lives inside the fromItem != null branch, while the else // without from branch prints preWhere / where only.

SQL Example:

SELECT 1 GROUP BY 1 HAVING 1 = 1
SELECT 1 QUALIFY 1 = 1
SELECT 1 WINDOW w AS (ORDER BY 1)
SELECT 1 START WITH 1 = 1 CONNECT BY LEVEL <= 1
SELECT 1 PREFERRING HIGH 1

All five parse on current master (ad69ecc), and each toString() returns SELECT 1:

IN : SELECT 1 GROUP BY 1 HAVING 1=1
OUT: SELECT 1

IN : SELECT 1 WINDOW w AS (ORDER BY 1)
OUT: SELECT 1

IN : SELECT 1 START WITH 1 = 1 CONNECT BY LEVEL <= 1
OUT: SELECT 1

WHERE survives (SELECT 1 WHERE 1 = 1 renders correctly), which shows the asymmetry.

Software Information:

• JSqlParser 5.4-SNAPSHOT, master ad69ecc
• JDK 17
• any RDBMS (renderer-level, dialect independent)