alamb commented on code in PR #12467:
URL: https://github.com/apache/datafusion/pull/12467#discussion_r1761723046
##########
datafusion/sql/src/expr/identifier.rs:
##########
@@ -186,7 +186,22 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
let s = &ids[0..ids.len()];
// safe unwrap as s can never be empty or exceed
the bounds
let (relation, column_name) =
form_identifier(s).unwrap();
- Ok(Expr::Column(Column::new(relation,
column_name)))
+ // sanity check on column
+ match schema
Review Comment:
I think we are trying to avoid matching on `Err` and converting to `Ok`
because each `Err` results in at least one `String` allocation (for the error
message)
Since this code is potentially invoked many times during planning the
allocations can add up and slow down planning
Is there any way to use a method that doesn't return `Err` here?
##########
datafusion/common/src/dfschema.rs:
##########
@@ -467,6 +464,36 @@ impl DFSchema {
.collect()
}
+ /// Find all fields that match the given name with qualifier and return
them with their qualifier
+ pub fn qualified_fields_with_qualified_name(
+ &self,
+ qualifier: &TableReference,
+ name: &str,
+ ) -> Vec<(Option<&TableReference>, &Field)> {
+ self.iter()
+ .filter(|(q, f)| match (qualifier, q) {
+ // field to lookup is qualified.
+ // current field is qualified and not shared between
relations, compare both
+ // qualifier and name.
+ (q, Some(field_q)) => q.resolved_eq(field_q) && f.name() ==
name,
+ // field to lookup is qualified but current field is
unqualified.
+ (qq, None) => {
+ // the original field may now be aliased with a name that
matches the
+ // original qualified name
+ let column = Column::from_qualified_name(f.name());
+ match column {
+ Column {
+ relation: Some(r),
+ name: column_name,
+ } => &r == qq && column_name == name,
+ _ => false,
+ }
Review Comment:
Another way to express this logic I would find clearer would be
```suggestion
if let Some(r) = column.relation.as_ref() {
r == qq && column.name == name
} else {
false
}
```
(though this is fine too)
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