fix(engine/sqlite): fix table_alias rules

changed rules to conform to fallback directive behavior

fix #2271

Author: orisano

internal/engine/sqlite/convert.go

@@ -769,6 +769,10 @@ func (c *cc) convertTablesOrSubquery(n []parser.ITable_or_subqueryContext) []ast
 				alias := from.Table_alias().GetText()
 				rv.Alias = &ast.Alias{Aliasname: &alias}
 			}
+			if from.Table_alias_fallback() != nil {
+				alias := identifier(from.Table_alias_fallback().GetText())
+				rv.Alias = &ast.Alias{Aliasname: &alias}
+			}
 
 			tables = append(tables, rv)
 		} else if from.Table_function_name() != nil {

internal/engine/sqlite/parser/SQLiteParser.g4

@@ -425,17 +425,15 @@ compound_select_stmt:
     )+ order_by_stmt? limit_stmt?
 ;
 
-table_or_subquery: (
-        (schema_name DOT)? table_name (AS_? table_alias)? (
-            INDEXED_ BY_ index_name
-            | NOT_ INDEXED_
-        )?
-    )
-    | (schema_name DOT)? table_function_name OPEN_PAR expr (COMMA expr)* CLOSE_PAR (
-        AS_? table_alias
-    )?
+table_or_subquery:
+    (schema_name DOT)? table_name (AS_? table_alias)? (INDEXED_ BY_ index_name | NOT_ INDEXED_)?
+    | (schema_name DOT)? table_function_name OPEN_PAR expr (COMMA expr)* CLOSE_PAR (AS_? table_alias)?
     | OPEN_PAR (table_or_subquery (COMMA table_or_subquery)* | join_clause) CLOSE_PAR
     | OPEN_PAR select_stmt CLOSE_PAR (AS_? table_alias)?
+    | (schema_name DOT)? table_name (AS_? table_alias_fallback)? (INDEXED_ BY_ index_name | NOT_ INDEXED_)?
+    | (schema_name DOT)? table_function_name OPEN_PAR expr (COMMA expr)* CLOSE_PAR (AS_? table_alias_fallback)?
+    | OPEN_PAR (table_or_subquery (COMMA table_or_subquery)* | join_clause) CLOSE_PAR
+    | OPEN_PAR select_stmt CLOSE_PAR (AS_? table_alias_fallback)?
 ;
 
 result_column:
@@ -875,9 +873,9 @@ savepoint_name:
     any_name
 ;
 
-table_alias:
-    any_name
-;
+table_alias: IDENTIFIER | STRING_LITERAL;
+
+table_alias_fallback: any_name;
 
 transaction_name:
     any_name