示例：

select  'select a.xh,a.dj,a.xzb from xsjbxxb a where a.xzb=' || chr(39)  ||   a.xzb ||  chr(39)  ||   ' order by dj desc for update;'
from   xsjbxxb a

结果：

select a.xh,a.dj,a.xzb from xsjbxxb a where a.xzb='机191' order by dj desc for update;
select a.xh,a.dj,a.xzb from xsjbxxb a where a.xzb='自动化类195' order by dj desc for update;
select a.xh,a.dj,a.xzb from xsjbxxb a where a.xzb='印191' order by dj desc for update;

说明：

要显示的字符串用一对单引号表示

连接字符串的运算符是 ||

chr（39）表示单引号