hadoop中使用MapReduce单表关联案例: MapReduce:给出children-parents(孩子——父母)表,要求输出grandchild-grandparent(孙子——爷奶)表. 给出表: Tom Lucy Tom Jack Jone Lucy Jone Jack Lucy Mary Lucy Ben Jack Alice Jack Jesse Terry Alice Terry Jesse Philip Terry Philip Alma Mark Terry Mark
一.FOR ALL ENTRIES IN 案例 今天碰到工单报工统计分析表查询速度特别慢 经查看源代码: SELECT afpo~dwerk afko~aufnr afpo~matnr AS plnbez afpo~charg afpo~psmng afko~fevor afko~aufpl FROM afko INNER JOIN afpo ON afko~aufnr = afpo~aufnr INTO CORRESPONDING FIELDS OF T