Mryange commented on PR #66181:
URL: https://github.com/apache/doris/pull/66181#issuecomment-5163422352
我用ai分析了一下，好像rewrite的行为不一定是对的？
element_at(split_by_string('abc', ','), 1) = 'abc'
三者实际行为如下：
表达式 结果
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━━━━━
split_by_string('abc', ',') ['abc']
───────────────────────────── ─────────
element_at(['abc'], 1) 'abc'
───────────────────────────── ─────────
split_part('abc', ',', 1) NULL
所以原谓词为 TRUE，PR 改写后为 NULL，Filter 会错误地过滤掉这一行。
```
SELECT 'original_filter' AS test_case, COUNT(*) AS rows_kept
FROM (
SELECT CAST(number AS STRING) AS s
FROM numbers("number" = "1")
) t
WHERE element_at(split_by_string(s, ','), 1) = '0'
UNION ALL
SELECT 'rewritten_filter' AS test_case, COUNT(*) AS rows_kept
FROM (
SELECT CAST(number AS STRING) AS s
FROM numbers("number" = "1")
) t
WHERE split_part(s, ',', 1) = '0';
+------------------+-----------+
| test_case | rows_kept |
+------------------+-----------+
| original_filter | 1 |
| rewritten_filter | 0 |
+------------------+-----------+
```
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