feat(cube): Make comparison coercion convert strings to booleans

Author: srh

datafusion/expr-common/src/type_coercion/binary.rs

@@ -706,7 +706,8 @@ pub fn try_type_union_resolution_with_struct(
 ///
 /// When comparing numeric values and strings, both values will be coerced to
 /// strings.  For example when comparing `'2' > 1`,  the arguments will be
-/// coerced to `Utf8` for comparison
+/// coerced to `Utf8` for comparison.  Cubestore:  No, they get coerced to
+/// numeric.  Same with strings and booleans.
 pub fn comparison_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
     if lhs_type == rhs_type {
         // same type => equality is possible
@@ -721,7 +722,7 @@ pub fn comparison_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<D
         .or_else(|| null_coercion(lhs_type, rhs_type))
         // TODO upgrade DF: Look at non-comparison coercions and figure out desirable behavior
         .or_else(|| string_numeric_coercion_as_numeric(lhs_type, rhs_type))
-        .or_else(|| string_boolean_coercion(lhs_type, rhs_type))
+        .or_else(|| string_boolean_coercion_as_boolean(lhs_type, rhs_type))
         .or_else(|| string_temporal_coercion(lhs_type, rhs_type))
         .or_else(|| binary_coercion(lhs_type, rhs_type))
         .or_else(|| struct_coercion(lhs_type, rhs_type))
@@ -820,6 +821,18 @@ fn string_numeric_coercion_as_numeric(
     None
 }
 
+fn string_boolean_coercion_as_boolean(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
+    use arrow::datatypes::DataType::*;
+    match (lhs_type, rhs_type) {
+        (Utf8, Boolean) => Some(Boolean),
+        (LargeUtf8, Boolean) => Some(Boolean),
+        (Boolean, Utf8) => Some(Boolean),
+        (Boolean, LargeUtf8) => Some(Boolean),
+        _ => None,
+    }
+}
+
+
 /// Coerce `lhs_type` and `rhs_type` to a common type for the purposes of a comparison operation
 /// where one is boolean and one is `Utf8`/`LargeUtf8`.
 fn string_boolean_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {