如何使用 BigQuery 在 INT64 和二进制 STRING 之间进行转换？

Question

BigQuery 问题跟踪器上有一个 feature request 用于转换函数，例如在 INT64 和二进制 STRING 之间。除了使用 JavaScript UDF 之外，是否有解决方法？

Answer 1

是的，您可以使用 SQL 实现 INT64 和二进制 STRING 之间的转换，而不需要 JavaScript。这是一个例子：

CREATE TEMP FUNCTION ToBinary(x INT64) AS (
  (SELECT STRING_AGG(CAST(x >> bit & 0x1 AS STRING), '' ORDER BY bit DESC)
   FROM UNNEST(GENERATE_ARRAY(0, 63)) AS bit)
);

CREATE TEMP FUNCTION FromBinary(s STRING) AS (
  (SELECT SUM(CAST(c AS INT64) << (LENGTH(s) - 1 - bit))
   FROM UNNEST(SPLIT(s, '')) AS c WITH OFFSET bit)
);

SELECT x, ToBinary(x) AS binary, FromBinary(ToBinary(x)) AS roundtrip
FROM UNNEST([1, 123456, 9876543210, -1001]) AS x;

这个returns:

+------------+------------------------------------------------------------------+------------+
|     x      |                              binary                              | roundtrip  |
+------------+------------------------------------------------------------------+------------+
|          1 | 0000000000000000000000000000000000000000000000000000000000000001 |          1 |
|     123456 | 0000000000000000000000000000000000000000000000011110001001000000 |     123456 |
| 9876543210 | 0000000000000000000000000000001001001100101100000001011011101010 | 9876543210 |
|      -1001 | 1111111111111111111111111111111111111111111111111111110000010111 |      -1001 |
+------------+------------------------------------------------------------------+------------+

作为奖励，这里有一种在 INT64 和十六进制 STRING 之间转换的方法：

CREATE TEMP FUNCTION ToHex(x INT64) AS (
  (SELECT STRING_AGG(FORMAT('%02x', x >> (byte * 8) & 0xff), '' ORDER BY byte DESC)
   FROM UNNEST(GENERATE_ARRAY(0, 7)) AS byte)
);

CREATE TEMP FUNCTION FromHex(s STRING) AS (
  (SELECT SUM(CAST(CONCAT('0x', SUBSTR(s, byte * 2 + 1, 2)) AS INT64) << ((LENGTH(s) - (byte + 1) * 2) * 4))
   FROM UNNEST(GENERATE_ARRAY(1, LENGTH(s) / 2)) WITH OFFSET byte)
);

SELECT x, ToHex(x) AS hex, FromHex(ToHex(x)) AS roundtrip
FROM UNNEST([1, 123456, 9876543210, -1001]) AS x;

这个returns:

+------------+------------------+------------+
|     x      |       hex        | roundtrip  |
+------------+------------------+------------+
|          1 | 0000000000000001 |          1 |
|     123456 | 000000000001e240 |     123456 |
| 9876543210 | 000000024cb016ea | 9876543210 |
|      -1001 | fffffffffffffc17 |      -1001 |
+------------+------------------+------------+

（八进制转换留作 reader 的练习。）

Answer 2

也可以使用 CAST 和 FORMAT:

整数转十六进制：

SELECT FORMAT("%X", my_int) AS my_hex ...

十六进制转整数

SELECT CAST(my_hex AS INT64) AS my_int ...

Answer 3

2021 年更新：

from_binary and to_binary 功能已集成到官方 bqutil public 项目中。

将二进制表示形式转换为整数：

SELECT bqutil.fn.from_binary('111')

7

将整数转换为二进制表示：

SELECT bqutil.fn.to_binary(7)

0000000000000000000000000000000000000000000000000000000000000111

如何使用 BigQuery 在 INT64 和二进制 STRING 之间进行转换？

How can I convert between INT64 and binary STRING using BigQuery?

google-bigquery

bigquery-standard-sql