Weijun-H commented on code in PR #11542:
URL: https://github.com/apache/datafusion/pull/11542#discussion_r1685875278
##########
datafusion/expr/src/expr_schema.rs:
##########
@@ -112,7 +112,22 @@ impl ExprSchemable for Expr {
Expr::OuterReferenceColumn(ty, _) => Ok(ty.clone()),
Expr::ScalarVariable(ty, _) => Ok(ty.clone()),
Expr::Literal(l) => Ok(l.data_type()),
- Expr::Case(case) => case.when_then_expr[0].1.get_type(schema),
+ // Expr::Case(case) => case.when_then_expr[0].1.get_type(schema),
+ Expr::Case(case) => {
+ let then_type = case.when_then_expr[0].1.get_type(schema)?;
+ if !then_type.is_null() {
+ return Ok(then_type);
+ }
+
+ let else_type = case
+ .else_expr
+ .as_ref()
+ .map_or(Ok(DataType::Null), |e| e.get_type(schema))?;
+ if !else_type.is_null() {
+ return Ok(else_type);
+ }
+ Ok(DataType::Int64)
Review Comment:
Current implementation will return the first non-NULL type among the then
and else expressions.
``` shell
> select arrow_typeof(CASE data WHEN 1 THEN NULL WHEN 2 THEN 'FOO' ELSE NULL
END )from example;
+------------------------------------------------------------------------------------------------------+
| arrow_typeof(CASE example.data WHEN Int64(1) THEN NULL WHEN Int64(2) THEN
Utf8("FOO") ELSE NULL END) |
+------------------------------------------------------------------------------------------------------+
| Utf8
|
| Utf8
|
| Utf8
|
| Utf8
|
+------------------------------------------------------------------------------------------------------+
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
