ALTER TABLE "public"."doc_statistics_definition" 
  ADD COLUMN "unit" varchar(50) COLLATE "pg_catalog"."default" DEFAULT ''::character varying;
   COMMENT ON COLUMN "public"."doc_statistics_definition"."unit" IS '统计值单位（如“次”“mg”“分钟”等）';
   
   -- 插入文档统计表格结构修改的迁移记录
INSERT INTO __MigrationsHistory (MigrationId, ProductVersion)
VALUES ('202509031300alter_table_doc_statistics_definiton', '1.0.0');