复制表结构及表数据:create table table_name_new as select * from table_name_old 复制表结构：create table table_name_new like table_name_old复制表数据：insert into K20_JDBC_TMP select * from K20_JDBC; 设置为空字段数据为-1：update K20_JDBC_TMP set JDBCTIME_MS=-1 WHERE JDBCTIME_MS is NULL;清空表数据:truncate table K20_JDBC_TMP重命名表名：ALTER TABLE old_name RENAME TO new_name或者rename table to table_new添加字段的语法：alter table tablename add (column datatype [default value][null/not null],….);alter table K20_JDBC_TMP2 add T1 CHAR(20) default null; //默认允许为空修改字段的语法：alter table tablename modify (column datatype [default value][null/not null],….);alter table K20_JDBC_TMP2 modify T1 CHAR(30) default null;删除字段的语法：alter table tablename drop (column);alter table K20_JDBC_TMP2 drop column T1;比较两个表数据差异：select * from B minus select * from Aselecet pno,cno from A minus select pno,cno from B比较两张表结构相同的表，并将不同的数据插入第三张表中。insert into K20_JDBC_TMP2(TMZDIFF,WRITETIME,NODE,TIMESTAMP,IP,NODENAME,SERVERNAME,PROVIDERNAME,JDBCNAME,CREATECOUNT,CLOSECOUNT,POOLSIZE,FREEPOOLSIZE,USEDMAX_PCT,JDBCTIME,WAITTIME,USETIME,WAITINGTHREADCOUNT,JDBCTIME_MS,WAITTIME_MS,USETIME_MS) select * from K20_JDBC MINUS SELECT * FROM K20_JDBC_TMP