Binary 计数';1';红移列中每个位位置的值
我的红移表中有一个BIGINT列,我想要一个查询:Binary 计数';1';红移列中每个位位置的值,binary,bit-manipulation,aggregate-functions,amazon-redshift,bitcount,Binary,Bit Manipulation,Aggregate Functions,Amazon Redshift,Bitcount,我的红移表中有一个BIGINT列,我想要一个查询: 计算此列所有行中二进制值的每个位位置出现值“1”的次数 将以一种方式显示它,我将能够采取x顶部位的位置 例如(为了简化示例,我已经将整数值写成二进制): 在这种情况下,我将能够得到前五位的位置:(3,4,6,7,2) 注意:一列最多可以有64位的位置。您可以使用位和&检查每个位置 下面是一个跨行的示例: SELECT SUM(CASE WHEN bit_col & 64 > 0 THEN 1 ELSE 0 END) "100000
注意:一列最多可以有64位的位置。您可以使用位和
&
检查每个位置
下面是一个跨行的示例:
SELECT SUM(CASE WHEN bit_col & 64 > 0 THEN 1 ELSE 0 END) "1000000"
, SUM(CASE WHEN bit_col & 32 > 0 THEN 1 ELSE 0 END) "0100000"
, SUM(CASE WHEN bit_col & 16 > 0 THEN 1 ELSE 0 END) "0010000"
, SUM(CASE WHEN bit_col & 8 > 0 THEN 1 ELSE 0 END) "0001000"
, SUM(CASE WHEN bit_col & 4 > 0 THEN 1 ELSE 0 END) "0000100"
, SUM(CASE WHEN bit_col & 2 > 0 THEN 1 ELSE 0 END) "0000010"
, SUM(CASE WHEN bit_col & 1 > 0 THEN 1 ELSE 0 END) "0000001"
FROM my_table
;
1000000 | 0100000 | 0010000 | 0001000 | 0000100 | 0000010 | 0000001
---------+---------+---------+---------+---------+---------+---------
11 | 8 | 11 | 13 | 11 | 9 | 8
要在单个列中显示结果,需要使用union:
SELECT 1 AS "col", SUM(CASE WHEN bit_col & 64 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 2 AS "col", SUM(CASE WHEN bit_col & 32 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 3 AS "col", SUM(CASE WHEN bit_col & 16 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 4 AS "col", SUM(CASE WHEN bit_col & 8 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 5 AS "col", SUM(CASE WHEN bit_col & 4 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 6 AS "col", SUM(CASE WHEN bit_col & 2 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 7 AS "col", SUM(CASE WHEN bit_col & 1 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
ORDER BY bit_count DESC
;
position | bit_count
----------+-----------
6 | 6
7 | 6
4 | 4
5 | 4
2 | 0
3 | 0
1 | 0
编辑:如果你想要更具动态性的东西,你需要考虑使用UDF。您可以从my
f_bitwise_to_string
UDF开始作为模板,并从中添加所需内容 谢谢joe,问题是,正如前面提到的,我可能会有多达64位的列,我正在寻找更具动态性的内容(因此也可以对多个列进行强制转换)。转置的联合会完成了这项工作,但在这种情况下,如果可能的话,我会寻找更具动态性的东西。如果您想要更具动态性的东西,您需要使用UDF进行研究。您可以从myf_bitwise_to_string
UDF开始作为模板,并从中添加所需内容。
SELECT SUM(CASE WHEN bit_col & 64 > 0 THEN 1 ELSE 0 END) "1000000"
, SUM(CASE WHEN bit_col & 32 > 0 THEN 1 ELSE 0 END) "0100000"
, SUM(CASE WHEN bit_col & 16 > 0 THEN 1 ELSE 0 END) "0010000"
, SUM(CASE WHEN bit_col & 8 > 0 THEN 1 ELSE 0 END) "0001000"
, SUM(CASE WHEN bit_col & 4 > 0 THEN 1 ELSE 0 END) "0000100"
, SUM(CASE WHEN bit_col & 2 > 0 THEN 1 ELSE 0 END) "0000010"
, SUM(CASE WHEN bit_col & 1 > 0 THEN 1 ELSE 0 END) "0000001"
FROM my_table
;
1000000 | 0100000 | 0010000 | 0001000 | 0000100 | 0000010 | 0000001
---------+---------+---------+---------+---------+---------+---------
11 | 8 | 11 | 13 | 11 | 9 | 8
SELECT 1 AS "col", SUM(CASE WHEN bit_col & 64 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 2 AS "col", SUM(CASE WHEN bit_col & 32 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 3 AS "col", SUM(CASE WHEN bit_col & 16 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 4 AS "col", SUM(CASE WHEN bit_col & 8 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 5 AS "col", SUM(CASE WHEN bit_col & 4 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 6 AS "col", SUM(CASE WHEN bit_col & 2 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
UNION ALL SELECT 7 AS "col", SUM(CASE WHEN bit_col & 1 > 0 THEN 1 ELSE 0 END) AS bit_count FROM my_table
ORDER BY bit_count DESC
;
position | bit_count
----------+-----------
6 | 6
7 | 6
4 | 4
5 | 4
2 | 0
3 | 0
1 | 0