[
https://issues.apache.org/jira/browse/CALCITE-6762?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
xiaochen.zhou updated CALCITE-6762:
-----------------------------------
Description:
In Calcite, if the dialect's `supportsImplicitTypeCoercion` is set to `true`
(the default value is `true`), Calcite will remove the cast in the
`SqlImplementor#stripCastFromString()` method. For example, the following SQL:
```
FROM applydata_bigdata.kafka_topic_cluster_user_dept_month_one_day_msg_info
WHERE ymd > CAST('20240801' AS INTEGER)
ORDER BY ymd DESC
```
will be transformed into:
```
FROM
"hive"."applydata_bigdata"."kafka_topic_cluster_user_dept_month_one_day_msg_info"
WHERE "ymd" > '20240801'
ORDER BY "ymd" IS NULL DESC, "ymd" DESC LIMIT 200
```
Here, the `CAST` is removed.
However, in Presto, different data types cannot be directly compared, which
will result in an error.
!image-2025-01-05-02-16-32-718.png!
To avoid this issue, `supportsImplicitTypeCoercion` should be set to `false` in
`PrestoSqlDialect`.
> Preserving the CAST conversion for operands in Presto
> ---------------------------------------------------------
>
> Key: CALCITE-6762
> URL: https://issues.apache.org/jira/browse/CALCITE-6762
> Project: Calcite
> Issue Type: Improvement
> Reporter: xiaochen.zhou
> Priority: Major
> Attachments: image-2025-01-05-02-16-32-718.png
>
>
> In Calcite, if the dialect's `supportsImplicitTypeCoercion` is set to `true`
> (the default value is `true`), Calcite will remove the cast in the
> `SqlImplementor#stripCastFromString()` method. For example, the following SQL:
> ```
> FROM applydata_bigdata.kafka_topic_cluster_user_dept_month_one_day_msg_info
> WHERE ymd > CAST('20240801' AS INTEGER)
> ORDER BY ymd DESC
> ```
> will be transformed into:
> ```
> FROM
> "hive"."applydata_bigdata"."kafka_topic_cluster_user_dept_month_one_day_msg_info"
> WHERE "ymd" > '20240801'
> ORDER BY "ymd" IS NULL DESC, "ymd" DESC LIMIT 200
> ```
> Here, the `CAST` is removed.
> However, in Presto, different data types cannot be directly compared, which
> will result in an error.
> !image-2025-01-05-02-16-32-718.png!
> To avoid this issue, `supportsImplicitTypeCoercion` should be set to `false`
> in `PrestoSqlDialect`.
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