fix: make country alias sql idempotent

sql/20260420_sys_country_code_alias_codes.sql

@@ -1,5 +1,20 @@
-ALTER TABLE `sys_country_code`
-  ADD COLUMN `alias_codes` varchar(255) NOT NULL DEFAULT '' COMMENT '国家code别名集合(JSON数组)' AFTER `alias_name`;
+SET NAMES utf8mb4;
+
+SET @table_schema = DATABASE();
+SET @ddl = IF(
+    EXISTS(
+        SELECT 1
+        FROM information_schema.COLUMNS
+        WHERE TABLE_SCHEMA = @table_schema
+          AND TABLE_NAME = 'sys_country_code'
+          AND COLUMN_NAME = 'alias_codes'
+    ),
+    'SELECT 1',
+    "ALTER TABLE `sys_country_code` ADD COLUMN `alias_codes` varchar(255) NOT NULL DEFAULT '' COMMENT '国家code别名集合(JSON数组)' AFTER `alias_name`"
+);
+PREPARE stmt FROM @ddl;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
 
 UPDATE `sys_country_code`
 SET `alias_codes` = '["SA","KSA"]'