kylebrandt · April 1, 2025 18:33 · Apr 1, 2025
diff --git a/time_funcs.go b/time_funcs.go
@@ -0,0 +1,107 @@
+package sql
+
+import (
+	"context"
+	"time"
+
+	mysql "github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/types"
+)
+
+type timeRangeKey struct{}
+
+type TimeRange struct {
+	From time.Time
+	To   time.Time
+}
+
+func WithTimeRange(ctx context.Context, from, to time.Time) context.Context {
+	return context.WithValue(ctx, timeRangeKey{}, TimeRange{From: from, To: to})
+}
+
+func GetTimeRange(ctx context.Context) (TimeRange, bool) {
+	tr, ok := ctx.Value(timeRangeKey{}).(TimeRange)
+	return tr, ok
+
+}
+
+//
+// Expressions for time_from() and time_to()
+//
+
+type TimeFromExpr struct{}
+
+func (e *TimeFromExpr) Resolved() bool               { return true }
+func (e *TimeFromExpr) IsNullable() bool             { return false }
+func (e *TimeFromExpr) Children() []mysql.Expression { return nil }
+func (e *TimeFromExpr) WithChildren(...mysql.Expression) (mysql.Expression, error) {
+	return e, nil
+}
+func (e *TimeFromExpr) String() string   { return "time_from()" }
+func (e *TimeFromExpr) Type() mysql.Type { return types.Timestamp }
+func (e *TimeFromExpr) Eval(ctx *mysql.Context, _ mysql.Row) (interface{}, error) {
+	if tr, ok := GetTimeRange(ctx.Context); ok {
+		return tr.From, nil
+	}
+	return nil, nil
+}
+
+type TimeToExpr struct{}
+
+func (e *TimeToExpr) Resolved() bool               { return true }
+func (e *TimeToExpr) IsNullable() bool             { return false }
+func (e *TimeToExpr) Children() []mysql.Expression { return nil }
+func (e *TimeToExpr) WithChildren(...mysql.Expression) (mysql.Expression, error) {
+	return e, nil
+}
+func (e *TimeToExpr) String() string   { return "time_to()" }
+func (e *TimeToExpr) Type() mysql.Type { return types.Timestamp }
+func (e *TimeToExpr) Eval(ctx *mysql.Context, _ mysql.Row) (interface{}, error) {
+	if tr, ok := GetTimeRange(ctx.Context); ok {
+		return tr.To, nil
+	}
+	return nil, nil
+}
+
+//
+// sql.Function implementations
+//
+
+type timeFromFunction struct{}
+
+func (*timeFromFunction) isFunction() {}
+
+func (f *timeFromFunction) FunctionName() string {
+	return "time_from"
+}
+func (f *timeFromFunction) NewInstance(args []mysql.Expression) (mysql.Expression, error) {
+	return &TimeFromExpr{}, nil
+}
+
+type timeToFunction struct{}
+
+func (*timeToFunction) isFunction() {}
+
+func (f *timeToFunction) FunctionName() string {
+	return "time_to"
+}
+func (f *timeToFunction) NewInstance(args []mysql.Expression) (mysql.Expression, error) {
+	return &TimeToExpr{}, nil
+}
+
+//
+// FunctionProvider to register both functions
+//
+
+type TimeFuncProvider struct{}
+
+func (p *TimeFuncProvider) Function(ctx *mysql.Context, name string) (mysql.Function, bool) {
+	switch name {
+	case "time_from":
+		return &timeFromFunction{}, true
+	case "time_to":
+		return &timeToFunction{}, true
+	default:
+		return nil, false
+	}
+}