impala插入数据的时候，出现报错：
[hs-170:21000] > insert into test_abc(fund_account, client_name, client_sex) values('1234567890123456789001', 'name1', '0');
Query: insert into test_abc(fund_account, client_name, client_sex) values('1234567890123456789001', 'name1', '0')
ERROR: AnalysisException: Possible loss of precision for target table 'wt_tmp.test_abc'.
Expression ''1234567890123456789001'' (type: STRING) would need to be cast to VARCHAR(32) for column 'fund_account'
出现这类错误的时候，你就看报错，它说把某个字段转成什么就把某个字段转成什么。上述报错中提示：
(type: STRING) would need to be cast to VARCHAR(32) for column 'fund_account'
意思是：这个输入格式为STRING的字段fund_account'字段需转换成格式VARCHAR(32)。
来看下表test_abc的结构：
[hs-170:21000] > show create table test_abc;
Query: show create table test_abc
+-------------------------------------------------------------------------------+
| result |
+-------------------------------------------------------------------------------+
| CREATE TABLE wt_tmp.test_abc ( |
| fund_account VARCHAR(32) COMMENT 'fund_account', |
| client_name VARCHAR(64) COMMENT 'client_name', |
| client_sex VARCHAR(32) COMMENT 'client_sex' |
| ) |
| STORED AS TEXTFILE |
| LOCATION 'hdfs://hs-171:xxx/user/xxx/wt_tmp.db/test_abc' |
| TBLPROPERTIES ('transient_lastDdlTime'='1542874679') |
+-------------------------------------------------------------------------------+
接下来执行改造过的插入语句：
insert into test_abc(fund_account, client_name, client_sex) values(cast(001 as VARCHAR(32)), cast('name1' as varchar(64)), cast(0 as varchar(32)));
insert into test_abc(fund_account, client_name, client_sex) values(cast(002 as VARCHAR(32)), cast('name2' as varchar(64)), cast(0 as varchar(32)));
insert into test_abc(fund_account, client_name, client_sex) values(cast(003 as VARCHAR(32)), cast('name3' as varchar(64)), cast(1 as varchar(32)));
insert into test_abc(fund_account, client_name, client_sex) values(cast(004 as VARCHAR(32)), cast('name4' as varchar(64)), cast(1 as varchar(32)));
insert into test_abc(fund_account, client_name, client_sex) values(cast(005 as VARCHAR(32)), cast('name5' as varchar(64)), cast(0 as varchar(32)));
insert into test_abc(fund_account, client_name, client_sex) values(cast(006 as VARCHAR(32)), cast('name6' as varchar(64)), cast(2 as varchar(32)));
查看数据：
[hs-170:21000] > select * from test_abc;
Query: select * from test_abc
+--------------+-------------+------------+
| fund_account | client_name | client_sex |
+--------------+-------------+------------+
| 2 | name2 | 0 |
| 1 | name1 | 0 |
| 6 | name6 | 2 |
| 5 | name5 | 0 |
| 4 | name4 | 1 |
| 3 | name3 | 1 |
+--------------+-------------+------------+
Fetched 6 row(s) in 1.29s
插入成功。
上述SQL为单条插入，也可以一次插入多条（与mysql插入方式一致）：
insert into test_abc(fund_account, client_name, client_sex) values(cast(007 as VARCHAR(32)), cast('name7' as varchar(64)), cast(2 as varchar(32))),(cast(008 as VARCHAR(32)), cast('name8' as varchar(64)), cast(0 as varchar(32)));