假设原始数据tier,pids 都为null。id=25,tier=1,parent_id=0,pids=null,如何实现更新 tier,和pids ,实现下面的展示效果。 
pids =parent_id +parent_id的pids;
tier 为当前数据结构序号
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tier pids parent_id id
2 25         25 26
3 26,25 26 27
3 26,25 26 28
3 26,25 26 34
3 26,25 26 36
3 26,25 26 47
3 26,25 26 89
3 26,25 26 95
3 26,25 26 99
3 26,25 26 102
3 26,25 26 105
3 26,25 26 109
3 26,25 26 112
3 26,25 26 127
3 26,25 26 151
4 27,26,25 27 29
4 27,26,25 27 30
4 27,26,25 27 31
4 27,26,25 27 32
4 27,26,25 27 33
4 27,26,25 27 35
4 27,26,25 27 37
4 27,26,25 27 38
4 28,26,25 28 39
4 34,26,25 34 40
4 34,26,25 34 43
4 27,26,25 27 44
4 36,26,25 36 45
4 36,26,25 36 46
4 27,26,25 27 49
4 27,26,25 27 50
4 36,26,25 36 55
4 34,26,25 34 58
4 34,26,25 34 59
4 27,26,25 27 61
4 27,26,25 27 69
4 36,26,25 36 70
4 34,26,25 34 81
4 34,26,25 34 86
4 27,26,25 27 90
4 34,26,25 34 92
4 27,26,25 27 100
4 34,26,25 34 108
4 34,26,25 34 113
4 34,26,25 34 115
4 34,26,25 34 117
4 34,26,25 34 124
4 34,26,25 34 125
4 27,26,25 27 126
4 27,26,25 27 133
4 34,26,25 34 148
4 34,26,25 34 149
4 27,26,25 27 154
4 27,26,25 27 155
4 27,26,25 27 169