根据条件在 apache pig 中加入两个别名
join two aliases in apache pig based on a condition
我想加入两个 aliases/relations,
say A has keys : a,b,c
and B has keys : x,y,z
所以应该是：
C = JOIN A by a, (IF B.x matches "foo.*" then pick y else z)
如上logic.How我可以这样做吗？
我的回答：
只需根据条件生成一个键，然后通过该键加入
例如
BB = foreach B generate x,y,z,(x matches "foo.*") ? y : z as matchkey;
C = join A by a, BB by matchkey;
dump c;
我想加入两个 aliases/relations,
say A has keys : a,b,c
and B has keys : x,y,z
所以应该是：
C = JOIN A by a, (IF B.x matches "foo.*" then pick y else z)
如上logic.How我可以这样做吗？
我的回答：
只需根据条件生成一个键，然后通过该键加入
例如
BB = foreach B generate x,y,z,(x matches "foo.*") ? y : z as matchkey;
C = join A by a, BB by matchkey;
dump c;