produce a better error when a user tries to sort something unsortable (#2324)

(cherry picked from commit 1ce3a1c103)

sql3/errors.go

@@ -80,6 +80,7 @@ const (
 	// expected errors
 	ErrExpectedColumnReference         errors.Code = "ErrExpectedColumnReference"
 	ErrExpectedSortExpressionReference errors.Code = "ErrExpectedSortExpressionReference"
+	ErrExpectedSortableExpression      errors.Code = "ErrExpectedSortableExpression"
 
 	// call errors
 	ErrCallUnknownFunction                  errors.Code = "ErrCallUnknownFunction"
@@ -531,6 +532,13 @@ func NewErrExpectedSortExpressionReference(line, col int) error {
 	)
 }
 
+func NewErrExpectedSortableExpression(line, col int, typeName string) error {
+	return errors.New(
+		ErrExpectedSortExpressionReference,
+		fmt.Sprintf("[%d:%d] unable to sort a column of type '%s'", line, col, typeName),
+	)
+}
+
 // calls
 
 func NewErrCallParameterCountMismatch(line, col int, functionName string, formalCount, actualCount int) error {

sql3/parser/astdatatype.go

@@ -9,6 +9,7 @@ import (
 	"github.com/featurebasedb/featurebase/v3/pql"
 )
 
+// TODO(pok) make all these lower case
 const (
 	FieldTypeBool             = "BOOL"
 	FieldTypeDecimal          = "DECIMAL"

sql3/planner/compileselect.go

@@ -124,6 +124,12 @@ func (p *ExecutionPlanner) compileSelectStatement(stmt *parser.SelectStatement,
 			// get the data type from the projection
 			projDataType := projections[index].Type()
 
+			// don't let a sort happen on something unsortable right now
+			switch projDataType.(type) {
+			case *parser.DataTypeStringSet, *parser.DataTypeIDSet:
+				return nil, sql3.NewErrExpectedSortableExpression(0, 0, projDataType.TypeDescription())
+			}
+
 			f := &OrderByExpression{
 				Index:    index,
 				ExprType: projDataType,

sql3/test/defs/defs.go

@@ -15,6 +15,7 @@ var TableTests []TableTest = []TableTest{
 
 	selectTests,
 	selectKeyedTests,
+	orderByTests,
 
 	topTests,
 

sql3/test/defs/defs_orderby.go

@@ -0,0 +1,39 @@
+package defs
+
+var orderByTests = TableTest{
+	name: "orderByTests",
+	Table: tbl(
+		"order_by_test",
+		srcHdrs(
+			srcHdr("_id", fldTypeID),
+			srcHdr("an_int", fldTypeInt, "min 0", "max 100"),
+			srcHdr("an_id_set", fldTypeIDSet),
+			srcHdr("an_id", fldTypeID),
+			srcHdr("a_string", fldTypeString),
+			srcHdr("a_string_set", fldTypeStringSet),
+			srcHdr("a_decimal", fldTypeDecimal2),
+		),
+		srcRows(
+			srcRow(int64(1), int64(11), []int64{11, 12, 13}, int64(101), "str1", []string{"a1", "b1", "c1"}, float64(123.45)),
+			srcRow(int64(2), int64(22), []int64{21, 22, 23}, int64(201), "str2", []string{"a2", "b2", "c2"}, float64(234.56)),
+			srcRow(int64(3), int64(33), []int64{31, 32, 33}, int64(301), "str3", []string{"a3", "b3", "c3"}, float64(345.67)),
+			srcRow(int64(4), int64(44), []int64{41, 42, 43}, int64(401), "str4", []string{"a4", "b4", "c4"}, float64(456.78)),
+		),
+	),
+	SQLTests: []SQLTest{
+		{
+			name: "order-by-stringset",
+			SQLs: sqls(
+				"select * from order_by_test order by a_string_set asc",
+			),
+			ExpErr: "unable to sort a column of type 'STRINGSET'",
+		},
+		{
+			name: "order-by-idset",
+			SQLs: sqls(
+				"select * from order_by_test order by an_id_set asc",
+			),
+			ExpErr: "unable to sort a column of type 'IDSET'",
+		},
+	},
+}