alamb commented on code in PR #11961:
URL: https://github.com/apache/datafusion/pull/11961#discussion_r1715818843
##########
datafusion/sqllogictest/test_files/type_coercion.slt:
##########
@@ -49,3 +49,179 @@ select interval '1 month' - '2023-05-01'::date;
# interval - timestamp
query error DataFusion error: Error during planning: Cannot coerce arithmetic
expression Interval\(MonthDayNano\) \- Timestamp\(Nanosecond, None\) to valid
types
SELECT interval '1 month' - '2023-05-01 12:30:00'::timestamp;
+
+
+####################################
+## Test type coercion with UNIONs ##
+####################################
+
+# Disable optimizer to test only the analyzer with type coercion
+statement ok
+set datafusion.optimizer.max_passes = 0;
+
+statement ok
+set datafusion.explain.logical_plan_only = true;
+
+# Create test table
+statement ok
+CREATE TABLE orders(
+ order_id INT UNSIGNED NOT NULL,
+ customer_id INT UNSIGNED NOT NULL,
+ o_item_id VARCHAR NOT NULL,
+ qty INT NOT NULL,
+ price DOUBLE NOT NULL,
+ delivered BOOLEAN NOT NULL
+);
+
+# union_different_num_columns_error() / UNION
+query error Error during planning: Union schemas have different number of
fields: query 1 has 1 fields whereas query 2 has 2 fields
+SELECT order_id FROM orders UNION SELECT customer_id, o_item_id FROM orders
+
+# union_different_num_columns_error() / UNION ALL
+query error Error during planning: Union schemas have different number of
fields: query 1 has 1 fields whereas query 2 has 2 fields
+SELECT order_id FROM orders UNION ALL SELECT customer_id, o_item_id FROM orders
+
+# union_with_different_column_names()
+query TT
+EXPLAIN SELECT order_id from orders UNION ALL SELECT customer_id FROM orders
+----
+logical_plan
+01)Union
+02)--Projection: orders.order_id
+03)----TableScan: orders
+04)--Projection: orders.customer_id AS order_id
+05)----TableScan: orders
+
+# union_values_with_no_alias()
+query TT
+EXPLAIN SELECT 1, 2 UNION ALL SELECT 3, 4
+----
+logical_plan
+01)Union
+02)--Projection: Int64(1) AS Int64(1), Int64(2) AS Int64(2)
+03)----EmptyRelation
+04)--Projection: Int64(3) AS Int64(1), Int64(4) AS Int64(2)
+05)----EmptyRelation
+
+# union_with_incompatible_data_type()
+query error Error during planning: UNION Column 'Int64\(1\)' \(type: Int64\)
is not compatible with other type: Interval\(MonthDayNano\)
Review Comment:
I noticed that the error refers to the types in reverse order than they
appear in the query
The error message might be better if it were something more like
```
Incompatible inputs for Union. Previous inputs were of type
Interval\(MonthDayNano\), got incomaptible type 'Int64\(1\)' \(type: Int64\)
```
##########
datafusion/expr/src/logical_plan/builder.rs:
##########
@@ -1339,95 +1338,14 @@ pub(crate) fn validate_unique_names<'a>(
})
}
-pub fn project_with_column_index(
- expr: Vec<Expr>,
- input: Arc<LogicalPlan>,
- schema: DFSchemaRef,
-) -> Result<LogicalPlan> {
- let alias_expr = expr
- .into_iter()
- .enumerate()
- .map(|(i, e)| match e {
- Expr::Alias(Alias { ref name, .. }) if name !=
schema.field(i).name() => {
- e.unalias().alias(schema.field(i).name())
- }
- Expr::Column(Column {
- relation: _,
- ref name,
- }) if name != schema.field(i).name() =>
e.alias(schema.field(i).name()),
- Expr::Alias { .. } | Expr::Column { .. } => e,
- _ => e.alias(schema.field(i).name()),
- })
- .collect::<Vec<_>>();
-
- Projection::try_new_with_schema(alias_expr, input, schema)
- .map(LogicalPlan::Projection)
-}
-
/// Union two logical plans.
pub fn union(left_plan: LogicalPlan, right_plan: LogicalPlan) ->
Result<LogicalPlan> {
- let left_col_num = left_plan.schema().fields().len();
-
- // check union plan length same.
- let right_col_num = right_plan.schema().fields().len();
- if right_col_num != left_col_num {
- return plan_err!(
- "Union queries must have the same number of columns, (left is
{left_col_num}, right is {right_col_num})");
- }
-
- // create union schema
- let union_qualified_fields =
- zip(left_plan.schema().iter(), right_plan.schema().iter())
- .map(
- |((left_qualifier, left_field), (_right_qualifier,
right_field))| {
- let nullable = left_field.is_nullable() ||
right_field.is_nullable();
- let data_type = comparison_coercion(
- left_field.data_type(),
- right_field.data_type(),
- )
- .ok_or_else(|| {
- plan_datafusion_err!(
- "UNION Column {} (type: {}) is not compatible with column {}
(type: {})",
- right_field.name(),
- right_field.data_type(),
- left_field.name(),
- left_field.data_type()
- )
- })?;
- Ok((
- left_qualifier.cloned(),
- Arc::new(Field::new(left_field.name(), data_type,
nullable)),
- ))
- },
- )
- .collect::<Result<Vec<_>>>()?;
- let union_schema =
- DFSchema::new_with_metadata(union_qualified_fields, HashMap::new())?;
-
- let inputs = vec![left_plan, right_plan]
- .into_iter()
- .map(|p| {
- let plan = coerce_plan_expr_for_schema(&p, &union_schema)?;
- match plan {
- LogicalPlan::Projection(Projection { expr, input, .. }) => {
- Ok(Arc::new(project_with_column_index(
- expr,
- input,
- Arc::new(union_schema.clone()),
- )?))
- }
- other_plan => Ok(Arc::new(other_plan)),
- }
- })
- .collect::<Result<Vec<_>>>()?;
-
- if inputs.is_empty() {
- return plan_err!("Empty UNION");
- }
-
+ // Temporarily use the schema from the left input and later rely on the
analyzer to
Review Comment:
👍
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