hive转义字符

CREATE TABLE escape (id STRING, name STRING) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY '"'; 

LOAD DATA LOCAL INPATH '/home/tianzhao/book/escape.txt' 
OVERWRITE INTO TABLE escape; 

escape.txt的内容是： 
Joe"2\"3333 
Hank"2\"3333 

表没有转义，那么两个“都会当作字段分隔符，查询结果是： 
select * from escape; 
Joe 2\ 
Hank 2\ 


ALTER TABLE escape SET SERDEPROPERTIES ('escape.delim' = '\\'); 给表加上了转义字符\，\后面的字符会被转义，直接跳过，如果是分隔符不会被当作分隔符。查询结果是： 
select * from escape; 
Joe 2"3333 
Hank 2"3333 




CREATE TABLE escape2 (id STRING, name STRING) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY '"'; 

LOAD DATA LOCAL INPATH '/home/tianzhao/book/escape2.txt' 
OVERWRITE INTO TABLE escape2; 

escape2.txt 的内容是： 
Joe"2"3333"44 
Hank"2"3333"44 
实际数据比表的字段要多。 

select * from escape2; 
Joe 2 
Hank 2 


ALTER TABLE escape2 SET SERDEPROPERTIES ('serialization.last.column.takes.rest' = 'true'); 
serialization.last.column.takes.rest 的意思是最后一个字段的内容是否包含那些多余的数据： 
select * from escape2; 
Joe 2"3333"44 
Hank 2"3333"44