1.循环拼接-区别第一次
String _codes = "";
boolean isFirst = true;
for (Info Info : Infos) {
if (isFirst) {
_codes = _codes + Info.get_code();
isFirst = false;
} else {
_codes = _codes + "," + Info.get_code();
}
}
2.not exists 和select 1作用
not exists详解
SELECT i.*
FROM info i
LEFT JOIN period p ON i.prod_code = p.prod_code
WHERE
NOT EXISTS (SELECT 1 FROM task_exec e WHERE e.taskid in ())
日期转换
select to_char(to_date('20190612','yyyyMMdd'),'yyyy"年"MM"月"dd"日"') from dual
加7天
select to_char((to_date(:workdate,'yyyymmdd')+7),'yyyymmdd') from dual