hadoop - 字符串连接在 pig 中不起作用

Question

我在 hcatalog 中有一个表，它有 3 个字符串列。当我尝试连接字符串时，出现以下错误:

A = LOAD 'default.temp_table_tower' USING org.apache.hcatalog.pig.HCatLoader() ;
B = LOAD 'default.cdr_data' USING org.apache.hcatalog.pig.HCatLoader();
c = FOREACH A GENERATE CONCAT(mcc,'-',mnc) as newCid;

Could not resolve concat using imports: [, java.lang., org.apache.pig.builtin., org.apache.pig.impl.builtin.]

Could not infer the matching function for org.apache.pig.builtin.CONCAT as multiple or none of them fit. Please use an explicit cast

问题的根本原因可能是什么？

Answer 1

可能对 pig 中的连接有帮助

data1 包含:

(Maths,abc)
(Maths,def)
(Maths,ef)
(Maths,abc)
(Science,ac)
(Science,bc)
(Chemistry,xc)
(Telugu,xyz)

将模式视为子:Maths、Maths、Science....等和名称:abc、def、ef..等

X = FOREACH data1 GENERATE CONCAT(sub,CONCAT('@',name));

X 的 O/P 是:

(Maths@abc)
(Maths@def)
(Maths@ef)
(Maths@abc)
(Science@ac)
(Science@bc)
(Chemistry@xc)
(Telugu@xyz)