Enhance TypeAwareConversion to handle blob types for consistent SET/ENUM casting

- Extend TypeAwareConversion to handle IsBlobType in addition to IsTextOnly
- Use TypeAwareConversion consistently for both CHAR and BINARY conversions
- Remove direct ConvertToCollatedString call in binary conversion
- Update function documentation to reflect blob type support
- Simplify convertValue logic by using unified conversion approach

This ensures SET/ENUM types are converted properly for all string and binary
target types through a single, consistent code path.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: elianddb

sql/expression/convert.go

@@ -280,8 +280,7 @@ func (c *Convert) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 
 // convertValue converts a value from its current type to the specified target type for CAST/CONVERT operations.
 // It handles type-specific conversion logic and applies length/scale constraints where applicable.
-// For SET/ENUM types converting to text types, uses TypeAwareConversion for proper string representation.
-// For SET/ENUM types converting to binary types, converts to string first before applying binary conversion.
+// Uses TypeAwareConversion for SET/ENUM types to ensure proper string representation when converting to text or binary types.
 // If |typeLength| and |typeScale| are 0, they are ignored, otherwise they are used as constraints on the
 // converted type where applicable (e.g. Char conversion supports only |typeLength|, Decimal conversion supports
 // |typeLength| and |typeScale|).
@@ -293,10 +292,7 @@ func convertValue(ctx *sql.Context, val interface{}, castTo string, originType s
 	}
 	switch strings.ToLower(castTo) {
 	case ConvertToBinary:
-		// For SET/ENUM types, convert to string first since TypeAwareConversion only handles text types
-		if types.IsSet(originType) || types.IsEnum(originType) {
-			val, _, _ = types.ConvertToCollatedString(ctx, val, originType)
-		}
+		val, _ = types.TypeAwareConversion(ctx, val, originType, types.LongBlob)
 		b, _, err := types.LongBlob.Convert(ctx, val)
 		if err != nil {
 			return nil, nil

sql/types/conversion.go

@@ -737,14 +737,14 @@ func GeneralizeTypes(a, b sql.Type) sql.Type {
 
 // TypeAwareConversion converts a value to a specified type, with awareness of the value's original type. This is
 // necessary because some types, such as EnumType and SetType, are stored as ints and require information from the
-// original type to properly convert to strings.
+// original type to properly convert to strings and binary types.
 func TypeAwareConversion(ctx *sql.Context, val interface{}, originalType sql.Type, convertedType sql.Type) (interface{}, error) {
 	if val == nil {
 		return nil, nil
 	}
 	var converted interface{}
 	var err error
-	if IsTextOnly(convertedType) {
+	if IsTextOnly(convertedType) || IsBlobType(convertedType) {
 		converted, _, err = ConvertToCollatedString(ctx, val, originalType)
 	} else {
 		converted, _, err = convertedType.Convert(ctx, val)