sql联合查询一条select语句查询多个结果，显示

联合查询 举例&＃xff1a;

   select (select COUNT(id) from emailcontent where  state&＃61;1 and hasRead&＃61;0) as a,
    (select COUNT(id) from emailcontent where state&＃61;1 and hasRead&＃61;1) as b,
    (select COUNT(id) from emailcontent where  state&＃61;1 and hasRead&＃61;2) as c

结果集&＃xff1a; [{a&＃61;0, b&＃61;31, c&＃61;0}]

一条select语句实现多条查询语句