MySQL 当前年份和update关联多个表的问题

MySQL的当前年份：year(now()) 

插入当前年份：

insert into 表名 (字段) values ( year(now()) )

update关联多个表：

update 表名 as a1,表名 as a2 

SET a1.lqbz = '1', a1.gkzf = a2.Tdcj,a1.ksh = a2.Ksh

where a2. year= year(now()) and a1.ksxm = a2.xm and a1.sfdm = a2.sfDm