SQL Column 'count' not found.

select count(t1.id) from table t1 left join table2 t2 on t1.tid = t2.id

发现是别名问题

改为：select count(t1.id) as count from table t1 left join table2 t2 on t1.tid = t2.id

java.lang.IllegalArgumentException: argument type mismatch

是查询到的结果与返回类型不匹配