1 files changed, 89 insertions, 0 deletions
diff --git a/weed/query/engine/errors.go b/weed/query/engine/errors.go
new file mode 100644
index 000000000..6a297d92f
--- /dev/null
+++ b/weed/query/engine/errors.go
@@ -0,0 +1,89 @@
+package engine
+
+import "fmt"
+
+// Error types for better error handling and testing
+
+// AggregationError represents errors that occur during aggregation computation
+type AggregationError struct {
+	Operation string
+	Column    string
+	Cause     error
+}
+
+func (e AggregationError) Error() string {
+	return fmt.Sprintf("aggregation error in %s(%s): %v", e.Operation, e.Column, e.Cause)
+}
+
+// DataSourceError represents errors that occur when accessing data sources
+type DataSourceError struct {
+	Source string
+	Cause  error
+}
+
+func (e DataSourceError) Error() string {
+	return fmt.Sprintf("data source error in %s: %v", e.Source, e.Cause)
+}
+
+// OptimizationError represents errors that occur during query optimization
+type OptimizationError struct {
+	Strategy string
+	Reason   string
+}
+
+func (e OptimizationError) Error() string {
+	return fmt.Sprintf("optimization failed for %s: %s", e.Strategy, e.Reason)
+}
+
+// ParseError represents SQL parsing errors
+type ParseError struct {
+	Query   string
+	Message string
+	Cause   error
+}
+
+func (e ParseError) Error() string {
+	if e.Cause != nil {
+		return fmt.Sprintf("SQL parse error: %s (%v)", e.Message, e.Cause)
+	}
+	return fmt.Sprintf("SQL parse error: %s", e.Message)
+}
+
+// TableNotFoundError represents table/topic not found errors
+type TableNotFoundError struct {
+	Database string
+	Table    string
+}
+
+func (e TableNotFoundError) Error() string {
+	if e.Database != "" {
+		return fmt.Sprintf("table %s.%s not found", e.Database, e.Table)
+	}
+	return fmt.Sprintf("table %s not found", e.Table)
+}
+
+// ColumnNotFoundError represents column not found errors
+type ColumnNotFoundError struct {
+	Table  string
+	Column string
+}
+
+func (e ColumnNotFoundError) Error() string {
+	if e.Table != "" {
+		return fmt.Sprintf("column %s not found in table %s", e.Column, e.Table)
+	}
+	return fmt.Sprintf("column %s not found", e.Column)
+}
+
+// UnsupportedFeatureError represents unsupported SQL features
+type UnsupportedFeatureError struct {
+	Feature string
+	Reason  string
+}
+
+func (e UnsupportedFeatureError) Error() string {
+	if e.Reason != "" {
+		return fmt.Sprintf("feature not supported: %s (%s)", e.Feature, e.Reason)
+	}
+	return fmt.Sprintf("feature not supported: %s", e.Feature)
+}