支持不等于操作符：^=

src/common/backend/parser/scan.l

@@ -913,7 +913,7 @@ other			.
 						yyerror("operator too long");
 
 					/* Convert "!=" operator to "<>" for compatibility */
-					if (strcmp(yytext, "!=") == 0)
+					if (strcmp(yytext, "!=") == 0 || strcmp(yytext, "^=") == 0)
 					{
 						yylval->str = pstrdup("<>");
 						yyextra->is_hint_str = false;

src/test/regress/expected/select.out

@@ -904,3 +904,9 @@ LINE 1: select xmin from t, ft1 where t.a=ft1.a;
                             ^
 drop schema syscolofforeign cascade;
 NOTICE:  drop cascades to table t
+-- test ^=
+select 1 ^= 2;
+ ?column? 
+----------
+ t
+(1 row)

src/test/regress/sql/select.sql

@@ -270,3 +270,6 @@ select t.xmin from t, ft1 where t.a=ft1.a;
 select xmin from t, ft1 where t.a=ft1.a;
 
 drop schema syscolofforeign cascade;
+
+-- test ^=
+select 1 ^= 2;