Add TK_INTERSECT, TK_EXCEPT tokens and NODE_COMPOUND_QUERY, NODE_SET_OPERATION node types

Register INTERSECT and EXCEPT keywords in both MySQL and PostgreSQL keyword
tables. Update is_alias_start() blocklist to prevent these keywords from
being misinterpreted as implicit aliases.

Author: renecannao

include/sql_parser/common.h

@@ -164,6 +164,10 @@ enum class NodeType : uint16_t {
     NODE_DELETE_STMT,
     NODE_DELETE_USING_CLAUSE,  // PostgreSQL USING or MySQL USING form
 
+    // Compound query nodes
+    NODE_COMPOUND_QUERY,       // root for UNION/INTERSECT/EXCEPT
+    NODE_SET_OPERATION,        // operator (UNION, INTERSECT, EXCEPT) with ALL flag
+
     // Shared
     NODE_STMT_OPTIONS,         // LOW_PRIORITY, IGNORE, QUICK, DELAYED, etc.
     NODE_UPDATE_SET_ITEM,      // single col=expr pair (shared by INSERT SET and UPDATE SET)

include/sql_parser/keywords_mysql.h

@@ -49,6 +49,7 @@ inline constexpr KeywordEntry KEYWORDS[] = {
     {"DUPLICATE", 9, TokenType::TK_DUPLICATE},
     {"ELSE", 4, TokenType::TK_ELSE},
     {"END", 3, TokenType::TK_END},
+    {"EXCEPT", 6, TokenType::TK_EXCEPT},
     {"EXECUTE", 7, TokenType::TK_EXECUTE},
     {"EXISTS", 6, TokenType::TK_EXISTS},
     {"FALSE", 5, TokenType::TK_FALSE},
@@ -67,6 +68,7 @@ inline constexpr KeywordEntry KEYWORDS[] = {
     {"INDEX", 5, TokenType::TK_INDEX},
     {"INNER", 5, TokenType::TK_INNER},
     {"INSERT", 6, TokenType::TK_INSERT},
+    {"INTERSECT", 9, TokenType::TK_INTERSECT},
     {"INTO", 4, TokenType::TK_INTO},
     {"IS", 2, TokenType::TK_IS},
     {"ISOLATION", 9, TokenType::TK_ISOLATION},

include/sql_parser/keywords_pgsql.h

@@ -43,6 +43,7 @@ inline constexpr KeywordEntry KEYWORDS[] = {
     {"DROP", 4, TokenType::TK_DROP},
     {"ELSE", 4, TokenType::TK_ELSE},
     {"END", 3, TokenType::TK_END},
+    {"EXCEPT", 6, TokenType::TK_EXCEPT},
     {"EXECUTE", 7, TokenType::TK_EXECUTE},
     {"EXISTS", 6, TokenType::TK_EXISTS},
     {"FALSE", 5, TokenType::TK_FALSE},
@@ -58,6 +59,7 @@ inline constexpr KeywordEntry KEYWORDS[] = {
     {"INDEX", 5, TokenType::TK_INDEX},
     {"INNER", 5, TokenType::TK_INNER},
     {"INSERT", 6, TokenType::TK_INSERT},
+    {"INTERSECT", 9, TokenType::TK_INTERSECT},
     {"INTO", 4, TokenType::TK_INTO},
     {"IS", 2, TokenType::TK_IS},
     {"ISOLATION", 9, TokenType::TK_ISOLATION},

include/sql_parser/table_ref_parser.h

@@ -206,6 +206,8 @@ class TableRefParser {
             case TokenType::TK_ON:
             case TokenType::TK_USING:
             case TokenType::TK_UNION:
+            case TokenType::TK_INTERSECT:
+            case TokenType::TK_EXCEPT:
             case TokenType::TK_SEMICOLON:
             case TokenType::TK_RPAREN:
             case TokenType::TK_LPAREN:

include/sql_parser/token.h

@@ -75,6 +75,10 @@ enum class TokenType : uint16_t {
     TK_NOTHING,
     TK_RETURNING,
     TK_CONSTRAINT,
+
+    // Compound query operators
+    TK_INTERSECT,
+    TK_EXCEPT,
 };
 
 struct Token {