选出当天的日期的数据
select * from test_table where to_char(datetime, 'yyyy-mm-dd')=to_char(sysdate,'yyyy-mm-dd');
要想改变查询的结果，可以用 (case when then else end) as 句式
select (case when to_char(datetime, 'yyyy-mm-dd')=to_char(sysdate,'yyyy-mm-dd') then '今日' else '非今日' end) as datetime, shengfu from test_table;
repalce用法
replace(c1, c2, c3)
从c1字符串中找到c2字符，替换成c3字符
lpad用法
lpad(c1, length, c3)
返回没有length长，用c3再左边补齐
比length长，从右边截断
选两张表，结合
select t1.sname||'_VS_'||t2.sname from qiudui t1, qiudui t2 where t1.sname<>t2.sname;