alan910127 opened a new pull request, #15482:
URL: https://github.com/apache/datafusion/pull/15482
## Which issue does this PR close?
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- Closes #15161.
## Rationale for this change
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the issue then this section is not needed.
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Currently, DataFusion handles comparisons between numbers and string
literals differently from a number of databases. It coerces the number to a
string, whereas other databases cast the literal to the column type and emit an
error if the cast fails. This behavior can be unintuitive.
## What changes are included in this PR?
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sometimes worth providing a summary of the individual changes in this PR.
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Updated
[`TypeCoercionRewriter::coerce_binary_op`](https://github.com/apache/datafusion/blob/b4b8f6489c4a61ae2d27e99a2c897c9c594a15fb/datafusion/optimizer/src/analyzer/type_coercion.rs#L285)
to cast string literals to the column type if one is present on either side of
a comparison expression.
## Are these changes tested?
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- Updated existing tests to reflect the new type coercion behavior.
- In `push_down_filter.slt`, some `explain` tests now produce no output when
queries fail due to invalid casts. For now, I have updated these tests to
expect empty output, but further adjustments may be needed.
## Are there any user-facing changes?
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updated before approving the PR.
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Yes. Queries that previously coerced numbers into strings will now fail if
the string literal cannot be cast to the column type.
### Example
#### Before this change (success)
```sql
> CREATE TABLE t AS SELECT CAST(123 AS int) a;
> SELECT * FROM t WHERE a = '2147483648'; -- Not a valid i32
+---+
| a |
+---+
+---+
```
#### After this change (error)
```sql
> CREATE TABLE t AS SELECT CAST(123 AS int) a;
> SELECT * FROM t WHERE a = '2147483648'; -- Not a valid i32
type_coercion
caused by
Error during planning: Cannot coerce '2147483648' to type 'Int32'
```
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