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Posted to commits@doris.apache.org by GitBox <gi...@apache.org> on 2021/11/12 04:28:20 UTC
[GitHub] [incubator-doris] EmmyMiao87 opened a new issue #7102: [Feature] Reduce useless cast
EmmyMiao87 opened a new issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102
### Search before asking
- [X] I had searched in the [issues](https://github.com/apache/incubator-doris/issues?q=is%3Aissue) and found no similar issues.
### Description
Doris 在语义解析的时候，如果发现 Expr 中参数类型无法直接计算，就会增加 cast 逻辑。比如表结构 (k1 int, k2 bigint)，对于 Expr k1=k2 。原始表达式的类型为 k1(int) = k2(bigint) ，直接无法计算，所以需要通过 cast 表达式将 Expr 左孩子类型转成 bigint。则表达式变换成 cast(k1 as bigint) = k2。
### Use case
在语义解析判断参类型是否兼容的时候，有些类型会增加无用的 cast。
比如 k1(date) = k2(date) 也会转化为 cast(k1 as datetime) = cast(k2 as datetime)。
### Related issues
_No response_
### Are you willing to submit PR?
- [ ] Yes I am willing to submit a PR!
### Code of Conduct
- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 |
|---|---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
| BinaryPredicate | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right | 是否正确或可以优化 |
| --- | --- | --- | ---| --- |
| int | bigint | bigint| bigint | 正确|
# 精简代码逻辑
Type.getCmpType(Type t1, Type t2)
精简为从一个二维数组直接取值。
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[GitHub] [incubator-doris] EmmyMiao87 commented on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 commented on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
|---|---|---|
| BetweenPredicate | ||
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 |
|---|---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
| BinaryPredicate | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right | 是否正确或可以优化 |
| --- | --- | --- | ---| --- |
| int | bigint | bigint| bigint | 正确|
## 是否能精简统一各个cast 规则
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 | 是否正确 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()| |
| InPredicate | | |
| BinaryPredicate | | |
|
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right |
| --- | --- | --- | ---|
| int | bigint | bigint| bigint |
## 是否能精简统一各个cast 规则
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 | 是否正确 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()| |
| InPredicate | | |
| BinaryPredicate | | |
|
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType |
| --- | --- | --- |
|
## 是否能精简统一各个cast 规则
--
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
| BinaryPredicate | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right | 是否正确或可以优化 |
| --- | --- | --- | ---| --- |
| int | bigint | bigint| bigint | 正确|
## 是否能精简统一各个cast 规则
--
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
Cast 发生的位置
1. 多参表达式，各个参数之间兼容处理。
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则|
|---|---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType |
| --- | --- | --- |
|
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 | 是否正确 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()| |
| InPredicate | | |
| BinaryPredicate | | |
|
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType |
| --- | --- | --- |
|
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 |
|---|---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
| BinaryPredicate | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right | 是否正确或可以优化 |
| --- | --- | --- | ---| --- |
| int | bigint | bigint| bigint | 正确|
## 精简代码逻辑
Type.getCmpType(Type t1, Type t2)
精简为从一个二维数组直接取值。
--
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 | 是否正确 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()| |
| InPredicate | | |
| BinaryPredicate | | |
|
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType |
| --- | --- | --- |
|
## 是否能精简统一各个cast 规则
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
Cast 可能发生的位置
1. 多参表达式，各个参数之间兼容处理。
| Expr | cast 规则|
|---|---|
| BetweenPredicate | |
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
Cast 可能发生的位置
1. 多参表达式，各个参数之间兼容处理。
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
| Expr | cast 规则|
|---|---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType |
| --- | --- | --- |
|
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()|
| InPredicate | |
| BinaryPredicate | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right | 是否正确或可以优化 |
| --- | --- | --- | ---| --- |
| int | bigint | bigint| bigint | ---|
## 是否能精简统一各个cast 规则
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[GitHub] [incubator-doris] EmmyMiao87 edited a comment on issue #7102: [Feature] Reduce useless cast
Posted by GitBox <gi...@apache.org>.
EmmyMiao87 edited a comment on issue #7102:
URL: https://github.com/apache/incubator-doris/issues/7102#issuecomment-968508822
# 如何梳理所有 Expr 中各个类型转换是否存在无意义的 cast
1. 梳理各个不同表达式，及对应的cast 规则并记录。
2. 判断 cast 规则是否合理。
3. 是否能统一 cast 规则。
## 梳理
由于不同的表达式对多参兼容性的处理规则不太相同，所以首先需要整理各个表达式都使用了哪些 cast 规则。
比如对于 BetweenPredicate 来说，c1 between a and b 。 则需要找到 c1, a, b 三个参数都能兼容的类型。
```c1(int) between a (bigint) and b (varchar)``` 则会转化为 ```cast(c1 as varchar) between cast(a as varchar) and b(varchar)```
但对于 BinaryPredicate 来说，a = b 。当 a(int) = b(string) 的时候，他们的兼容类型是 int，则会转化为 ``` a = cast(b as int) ```
下表为不同表达式，以及他们对应的 cast 规则记录。
| Expr | cast 规则 | 是否正确 |
|---|---| ---|
| BetweenPredicate | Analyzer.castAllToCompatibleType()| |
| InPredicate | | |
| BinaryPredicate | | |
### 规则正确性判断
1. 对照 Mysql 行为，尽量保持一致
2. 查看 be 函数实现，是否存在该类型的函数。
3. 那种兼容策略性能更好，比如 int 和 date 对齐方式不同。
## 规则明细
Analyzer.castAllToCompatibleType(List<Exprs> exprs) 转化规则
将所有 Expr 转成一个大家都可兼容的类型
| Type1 | Type2 | CompatibleType | After swapping left and right |
| --- | --- | --- | ---|
| int | bigint | bigint| bigint |
## 是否能精简统一各个cast 规则
--
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