我有以下查询explain：
mysql> explain
select dd.data from dane dd
join test1.tag1 t1 on dd.id = t1.id
join test1.tag2 t2 on dd.id = t2.id
join test1.tag3 t3 on dd.id = t3.id
join test1.tag4 t4 on dd.id = t4.id
join test1.tag5 t5 on dd.id = t5.id
join test1.tag6 t6 on dd.id = t6.id
join test1.tag7 t7 on dd.id = t7.id
join test1.tag8 t8 on dd.id = t8.id
join test1.tag9 t9 on dd.id = t9.id
join test1.tag10 t10 on dd.id = t10.id …