alamb commented on code in PR #10746:
URL: https://github.com/apache/datafusion/pull/10746#discussion_r1632035977
##########
datafusion/sql/src/expr/mod.rs:
##########
@@ -274,6 +276,34 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
if let Some(format) = format {
return not_impl_err!("CAST with format is not supported:
{format}");
}
+ // <https://github.com/apache/datafusion/issues/10743> in this
issue, when we try to
+ // use SELECT '12345'::VARCHAR(2) to truncate a string, we
would like to throw an arrow since the length
+ // of the current string is longer than the given type.
+ // The reason to do the judgment here is that when we using
sqlparser to transfer 12345'::VARCHAR(2) to AST, it
+ // would generate a AST like
+ // ```
+ // Cast {
+ // kind: DoubleColon,
+ // expr: Value(SingleQuotedString("12345")),
+ // data_type: Varchar(Some(IntegerLength { length: 2,
unit: None })),
+ // format: None
+ // }
+ // ```
+ // but the arrow Datatype did not contain the length
information, so we need to the judgement here
+ if let ast::DataType::Varchar(Some(IntegerLength { length, ..
})) =
+ data_type
+ {
+ match &*expr {
+ SQLExpr::Value(Value::SingleQuotedString(s))
+ if s.len() > (length).try_into().unwrap() =>
Review Comment:
Or since we are returning an error, we could just erorr
something like this (untested)
```rust
let length: usize = length.try_into().map_err(|e| datafusion_plan_err!("Can
not convert {e} to length")?;
if s.len() > length {
...
}
```
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