mysql判断查询结果是否存在，存在输出1不存在输出0

 IF EXISTS (SELECT * FROM table WHERE condition) SELECT '1' ELSE SELECT '0';

类似这种语义，mysql中可以实现吗

IFNULL（a,b） 如果a不是NULL IFNULL()返回a，否则它返回b
或者

set @c = (SELECT count(*) as c FROM table WHERE condition)
if(@c>0) then
set @r = 1;
else
set @r = 0;
end if;
不知道是不是你想要的效果

select (case when (select count(1) from table WHERE condition) >0 when "select 1" else "select 0" end) from dual;

case when…… then ……else…… end

按照需求来看SELECT count(*) as c FROM table WHERE condition 获取到满足条件的个数不就好了，大于0就代表有数据