[fix](doc) v3.x/v2.1 zh: fix full-width commas in CTE example SQL

[boluor]

Problem

The Simple CTE example in the Chinese query-data/cte.md used full-width commas (， U+FF0C) inside the SQL code block:

WITH
  cte1 AS (SELECT a，b FROM table1)，
  cte2 AS (SELECT c，d FROM table2)
SELECT b，d FROM cte1 JOIN cte2
WHERE cte1.a = cte2.c;

Pasted as-is the statement fails to parse (errCode = 2 ... we meet an error when parsing). The English counterpart and the Nested CTE block on the same page already use half-width commas — only this one block was affected.

Fix

Replace the 4 full-width commas with half-width , in the simple-example SQL, making the ZH snippet identical to the canonical EN one. Chinese prose commas are left untouched.

Versions

• dev — N/A (ZH already rewritten, no longer contains this example)
• 4.x — N/A (same as dev)
• 3.x
• 2.1

Languages

• Chinese (only the ZH source carried the typo)
• English — N/A (already correct)
• Japanese — not touched

Verification

The snippet is an illustrative example over undefined table1/table2 (no setup, no expected-output table), so it has no cluster oracle to run end-to-end; correctness is established against the already-correct EN counterpart and the half-width Nested-CTE block on the same page. The change is a pure full-width→half-width comma typo fix confined to the SQL fence.