macroguo-ghy commented on code in PR #3721:
URL: https://github.com/apache/calcite/pull/3721#discussion_r1519303692
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core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorUtil.java:
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@@ -1381,6 +1399,54 @@ private static void adjustTypeForMultisetConstructor(
}
}
+ /**
+ * Adjusts the types of specified operands in a map operation to match a
given target type.
+ * This is particularly useful in the context of SQL operations involving
array functions,
+ * where it's necessary to ensure that all operands have consistent types
for the operation
+ * to be valid.
+ *
+ * <p>This method operates on the assumption that the operands to be
adjusted are part of a
+ * {@link SqlCall}, which is bound within a {@link SqlOperatorBinding}. The
operands to be
+ * cast are identified by their indexes within the {@code operands} list of
the {@link SqlCall}.
+ * The method performs a dynamic check to determine if an operand is a basic
call to a map.
+ * If so, it casts each element within the map to the target type.
+ * Otherwise, it casts the operand itself to the target type.
+ *
+ * <p>Example usage: For an operation like
+ * {@code map_values(map('foo', 1, 'bar', cast(1 as double)))},
+ * if map's value targetType is double, this method would ensure that the
value of the
+ * first map are cast to double.
+ *
+ * @param evenType the {@link RelDataType} to which the operands at even
positions should be cast
+ * @param oddType the {@link RelDataType} to which the operands at odd
positions should be cast
+ * @param sqlCallBinding the {@link SqlCallBinding} containing the operands
to be adjusted
+ */
+ private static void adjustTypeForMapFunctionConstructor(
+ RelDataType evenType, RelDataType oddType, SqlCallBinding
sqlCallBinding) {
+ SqlCall call = sqlCallBinding.getCall();
Review Comment:
Do you assume that `call` is a map constructor? I think the `call` can be a
column , a complex expr (like `map_concat(map('foo', 1), map('bar', 2))`)...
If we have a table like
```sql
create table t (id int, map_column map<integer, integer>);
```
when we execute a query like
```sql
select map_keys(map_column) from t;
```
I think your code will throw an exeception. Can you add more tests for your
PR?
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