Hive数据类型问题

Question

我们有3列来自来源，colA为3位数字，colB为5位数字，而ColC为5位数字。我们需要根据以上3列创建13位数的唯一ID

Query used - select colA*1000000000000 + colC*100000 + colC
Example - 

hive> select 123*1000000000000 + 12345*100000 + 12345;
OK
123001234512345 -- Not Expected
Time taken: 0.091 seconds, Fetched: 1 row(s)

进一步检查时，下面的配置单元查询没有给我正确的结果。

hive> !hive --version;
Hive 2.3.3-mapr-1904-r9
Git git://738a1fde0d37/root/opensource/mapr-hive-2.3/dl/mapr-hive-2.3 -r 265b539b942d0b9f4811b15880204dec5c0c7e1b
Compiled by root on Tue Aug 6 05:36:17 PDT 2019
From source with checksum 88f44b7532ffd7141c15cb5742e9cb51
hive> select cast(12345*1000000 as bigint);
OK
-539901888
Time taken: 0.126 seconds, Fetched: 1 row(s)
hive> select cast(12345*10000000 as bigint);
OK
-1104051584
Time taken: 0.02 seconds, Fetched: 1 row(s)
hive> select cast(12345*100000000 as bigint);
OK
1844386048
Time taken: 0.018 seconds, Fetched: 1 row(s)
hive> select cast(12345*1000000000 as bigint);
OK
1263991296
Time taken: 0.032 seconds, Fetched: 1 row(s)

鉴于以下查询有效-

hive> select cast(12345*10000000000 as bigint);
OK
123450000000000
Time taken: 0.017 seconds, Fetched: 1 row(s)
hive> select cast(12345*1000 as bigint);
OK
12345000
Time taken: 0.025 seconds, Fetched: 1 row(s)
hive> select cast(12345*10000 as bigint);
OK
123450000
Time taken: 0.035 seconds, Fetched: 1 row(s)
hive> select cast(12345*100000 as bigint);
OK
1234500000
Time taken: 0.247 seconds, Fetched: 1 row(s)

Answer 1

正如documentation解释：

默认情况下，假定整数文字为INT，除非数字超出INT的范围，在这种情况下，该数字将被解释为BIGINT，或者数字上存在以下后缀之一。

在此表达式中：

cast(12345*1000000 as bigint)

12345*1000000的结果强制转换为bigint。这并不意味着乘法是使用该类型完成的。为此，您需要强制转换before乘法：

12345 * cast(1000000 as bigint)

或者，您可以使用后缀：

12345L * 1000000L

注意，因为值已经是cast()，所以不需要显式的bigint。