Fix CTE with UNION

[StpMax]

Fix for queries with multiple CTE and UNION in it, like this one:

        WITH ta AS (
            SELECT 'a' AS a
            UNION
            SELECT 'b' AS a
        ), tb AS (
            SELECT 'c' AS a
            UNION
            SELECT 'd' AS a
        )
        SELECT a FROM ta
        UNION
        SELECT a FROM tb

[entelligence-ai-pr-reviews]

Review Summary

🏷️ Draft Comments (1)

Skipped posting 1 draft comments that were valid but scored below your review threshold (>13/15). Feel free to update them here.

mindsdb_sql_parser/parser.py (1)

1112-1118: ctes rule appends to a list using ctes = ctes + [...], which creates a new list each time and can cause O(n^2) time for many CTEs; use ctes.append(...) for O(n) total time.

📊 Impact Scores:

• Production Impact: 2/5
• Fix Specificity: 5/5
• Urgency Impact: 2/5
• Total Score: 9/15

🤖 AI Agent Prompt (Copy & Paste Ready):

In mindsdb_sql_parser/parser.py, lines 1112-1118, the `ctes` rule currently appends to the list using `ctes = ctes + [...]`, which is O(n^2) for many CTEs. Change this to use `ctes.append(...)` instead, to ensure O(n) total time for large numbers of CTEs. Preserve the original logic and indentation.

---

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
mindsdb_sql_parser
__about__.py	10	10	0%	1–10
__init__.py	119	23	81%	44, 48, 53, 98, 115, 118, 139–158, 165–166
lexer.py	280	21	92%	368, 370, 372, 384, 386, 388, 394–412
logger.py	19	4	79%	14, 17, 23, 26
parser.py	1107	32	97%	129, 133, 288, 313, 419, 605, 622, 646–647, 868, 922, 999, 1100, 1154, 1164, 1203–1204, 1233, 1244, 1327, 1403, 1442, 1478, 1671–1672, 1847–1848, 2024, 2032, 2085–2088
utils.py	46	4	91%	73–79
mindsdb_sql_parser/ast
base.py	36	5	86%	13, 28, 31, 46, 51
create.py	80	12	85%	23–31, 92–97
drop.py	52	2	96%	10, 13
insert.py	63	4	94%	39–41, 46
show.py	48	1	98%	18
update.py	53	5	91%	40–42, 75–76
mindsdb_sql_parser/ast/mindsdb
knowledge_base.py	97	1	99%	80
mindsdb_sql_parser/ast/select
case.py	37	1	97%	22
constant.py	36	1	97%	23
data.py	11	4	64%	10–12, 15, 19
identifier.py	83	11	87%	56, 104–112, 122
native_query.py	13	1	92%	25
operation.py	139	4	97%	57, 66, 178, 202
parameter.py	15	2	87%	17, 20
select.py	109	3	97%	160–165
star.py	12	2	83%	8–9
TOTAL	3392	153	95%

Tests	Skipped	Failures	Errors	Time
304	0 💤	0 ❌	0 🔥	12.810s ⏱️