added tests for decimal

core/types/schema.go

@@ -1237,6 +1237,10 @@ func (c *DataType) Equals(other *DataType) bool {
 }
 
 func (c *DataType) IsNumeric() bool {
+	if c.IsArray {
+		return false
+	}
+
 	return c.Name == intStr || c.Name == DecimalStr || c.Name == uint256Str || c.Name == unknownStr
 }
 

internal/engine/execution/procedure.go

@@ -577,6 +577,54 @@ func (p *preparedProcedure) shapeReturn(result *sql.ResultSet) error {
 
 	for i, col := range p.returns.Fields {
 		result.Columns[i] = col.Name
+
+		// if the column is a decimal or a decimal array, we need to convert the values to
+		// the specified scale and precision
+		if col.Type.Name == types.DecimalStr {
+			// if it is an array, we need to convert each value in the array
+			if col.Type.IsArray {
+				for _, row := range result.Rows {
+					if row[i] == nil {
+						continue
+					}
+
+					arr, ok := row[i].([]any)
+					if !ok {
+						return fmt.Errorf("shapeReturn: expected decimal array, got %T", row[i])
+					}
+
+					for _, v := range arr {
+						if v == nil {
+							continue
+						}
+						dec, ok := v.(*decimal.Decimal)
+						if !ok {
+							return fmt.Errorf("shapeReturn: expected decimal, got %T", dec)
+						}
+						err := dec.SetPrecisionAndScale(col.Type.Metadata[0], col.Type.Metadata[1])
+						if err != nil {
+							return err
+						}
+					}
+				}
+			} else {
+				for _, row := range result.Rows {
+					if row[i] == nil {
+						continue
+					}
+
+					dec, ok := row[i].(*decimal.Decimal)
+					if !ok {
+						return fmt.Errorf("shapeReturn: expected decimal, got %T", row[i])
+					}
+
+					err := dec.SetPrecisionAndScale(col.Type.Metadata[0], col.Type.Metadata[1])
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
 	}
 
 	return nil

internal/engine/execution/queries.go

@@ -318,7 +318,6 @@ func deleteSchema(ctx context.Context, tx sql.TxMaker, dbid string) error {
 }
 
 // setContextualVars sets the contextual variables for the given postgres session.
-// TODO: use this function for actions too.
 func setContextualVars(ctx context.Context, db sql.DB, data *common.ExecutionData) error {
 	// for contextual parameters, we use postgres's current_setting()
 	// feature for setting session variables. For example, @caller

internal/engine/integration/procedure_test.go

@@ -14,9 +14,11 @@ import (
 	"github.com/kwilteam/kwil-db/common/sql"
 	"github.com/kwilteam/kwil-db/core/crypto"
 	"github.com/kwilteam/kwil-db/core/types"
+	"github.com/kwilteam/kwil-db/core/types/decimal"
 	"github.com/kwilteam/kwil-db/core/utils/order"
 	"github.com/kwilteam/kwil-db/internal/engine/execution"
 	"github.com/kwilteam/kwil-db/parse"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -256,6 +258,25 @@ func Test_Procedures(t *testing.T) {
 			}`,
 			outputs: [][]any{{int64(1), int64(3)}},
 		},
+		{
+			name: "sum",
+			procedure: `procedure sum() public view returns (sum decimal(1000,0)) {
+				for $row in select sum(user_num) as s from users {
+					return $row.s;
+				}
+			}`,
+			outputs: [][]any{{mustDecimal("6", 1000, 0)}},
+		},
+		{
+			name: "decimal array",
+			procedure: `procedure decimal_array() public view returns (decimals decimal(2,1)[]) {
+				$a := 2.5;
+				$b := 3.5;
+				$c := $a/$b;
+				return [$a, $b, $c];
+			}`,
+			outputs: [][]any{{[]any{mustDecimal("2.5", 2, 1), mustDecimal("3.5", 2, 1), mustDecimal("0.7", 2, 1)}}},
+		},
 	}
 
 	for _, test := range tests {
@@ -301,13 +322,31 @@ func Test_Procedures(t *testing.T) {
 			for i, output := range test.outputs {
 				require.Len(t, res.Rows[i], len(output))
 				for j, val := range output {
+					if dec, ok := val.(*decimal.Decimal); ok {
+						received := res.Rows[i][j].(*decimal.Decimal)
+
+						assert.Equal(t, dec.String(), received.String())
+						assert.Equal(t, dec.Precision(), received.Precision())
+						assert.Equal(t, dec.Scale(), received.Scale())
+						continue
+					}
+
 					require.Equal(t, val, res.Rows[i][j])
 				}
 			}
 		})
 	}
 }
 
+func mustDecimal(val string, precision, scale uint16) *decimal.Decimal {
+	d, err := decimal.NewExplicit(val, precision, scale)
+	if err != nil {
+		panic(err)
+	}
+
+	return d
+}
+
 func Test_ForeignProcedures(t *testing.T) {
 	type testcase struct {
 		name string

parse/functions.go

@@ -563,15 +563,32 @@ var (
 		},
 		"sum": {
 			ValidateArgs: func(args []*types.DataType) (*types.DataType, error) {
+				// per https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-NUMERIC-TABLE
+				// the result of sum will be made a decimal(1000, 0)
 				if len(args) != 1 {
 					return nil, wrapErrArgumentNumber(1, len(args))
 				}
 
-				if !args[0].EqualsStrict(types.IntType) {
-					return nil, wrapErrArgumentType(types.IntType, args[0])
+				if !args[0].IsNumeric() {
+					return nil, fmt.Errorf("expected argument to be numeric, got %s", args[0].String())
 				}
 
-				return types.IntType, nil
+				var retType *types.DataType
+				switch {
+				case args[0].EqualsStrict(types.IntType):
+					retType = decimal1000.Copy()
+				case args[0].Name == types.DecimalStr:
+					retType = args[0].Copy()
+					retType.Metadata[0] = 1000 // max precision
+				case args[0].EqualsStrict(types.Uint256Type):
+					retType = decimal1000.Copy()
+				case args[0].EqualsStrict(types.UnknownType):
+					retType = types.UnknownType.Copy()
+				default:
+					panic(fmt.Sprintf("unexpected numeric type: %s", retType.String()))
+				}
+
+				return retType, nil
 			},
 			IsAggregate: true,
 			PGFormat: func(inputs []string, distinct bool, star bool) (string, error) {
@@ -653,6 +670,17 @@ func defaultFormat(name string) FormatFunc {
 	}
 }
 
+// decimal1000 is a decimal type with a precision of 1000.
+var decimal1000 *types.DataType
+
+func init() {
+	var err error
+	decimal1000, err = types.NewDecimalType(1000, 0)
+	if err != nil {
+		panic(fmt.Sprintf("failed to create decimal type: 1000, 0: %v", err))
+	}
+}
+
 func errDistinct(funcName string) error {
 	return fmt.Errorf(`%w: cannot use DISTINCT with function "%s"`, ErrFunctionSignature, funcName)
 }

parse/parse_test.go

@@ -1566,6 +1566,88 @@ func Test_Procedure(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "sum types - failure",
+			proc: `
+			$sum := 0;
+			for $row in select sum(id) as id from users {
+				$sum := $sum + $row.id;
+			}
+			`,
+			// this should error, since sum returns numeric
+			err: parse.ErrType,
+		},
+		{
+			name: "sum types - success",
+			proc: `
+			$sum decimal(1000,0);
+			for $row in select sum(id) as id from users {
+				$sum := $sum + $row.id;
+			}
+			`,
+			want: &parse.ProcedureParseResult{
+				Variables: map[string]*types.DataType{
+					"$sum": mustNewDecimal(1000, 0),
+				},
+				CompoundVariables: map[string]struct{}{
+					"$row": {},
+				},
+				AST: []parse.ProcedureStmt{
+					&parse.ProcedureStmtDeclaration{
+						Variable: exprVar("$sum"),
+						Type:     mustNewDecimal(1000, 0),
+					},
+					&parse.ProcedureStmtForLoop{
+						Receiver: exprVar("$row"),
+						LoopTerm: &parse.LoopTermSQL{
+							Statement: &parse.SQLStatement{
+								SQL: &parse.SelectStatement{
+									SelectCores: []*parse.SelectCore{
+										{
+											Columns: []parse.ResultColumn{
+												&parse.ResultColumnExpression{
+													Expression: &parse.ExpressionFunctionCall{
+														Name: "sum",
+														Args: []parse.Expression{
+															exprColumn("", "id"),
+														},
+													},
+													Alias: "id",
+												},
+											},
+											From: &parse.RelationTable{
+												Table: "users",
+											},
+										},
+									},
+									// If there is an aggregate clause with no group by, then no ordering is applied.
+								},
+							},
+						},
+						Body: []parse.ProcedureStmt{
+							&parse.ProcedureStmtAssign{
+								Variable: exprVar("$sum"),
+								Value: &parse.ExpressionArithmetic{
+									Left:     exprVar("$sum"),
+									Operator: parse.ArithmeticOperatorAdd,
+									Right:    &parse.ExpressionFieldAccess{Record: exprVar("$row"), Field: "id"},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			// this is a regression test for a previous bug
+			name: "adding arrays",
+			proc: `
+			$arr1 := [1,2,3];
+			$arr2 := [4,5,6];
+			$arr3 := $arr1 + $arr2;
+			`,
+			err: parse.ErrType,
+		},
 	}
 
 	for _, tt := range tests {
@@ -1644,6 +1726,14 @@ func exprVar(n string) *parse.ExpressionVariable {
 	}
 }
 
+func mustNewDecimal(precision, scale uint16) *types.DataType {
+	dt, err := types.NewDecimalType(precision, scale)
+	if err != nil {
+		panic(err)
+	}
+	return dt
+}
+
 // exprLit makes an ExpressionLiteral.
 // it can only make strings and ints
 func exprLit(v any) *parse.ExpressionLiteral {