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BIT_SHIFT_LEFT

bit_shift_left

description

syntax

BIT_SHIFT_LEFT(BIGINT x, TINYINT c)

将 BIGINT 类型的 x 向左移动 c 位,并将结果作为 BIGINT 返回。 如果 c 小于 0,则返回零。

example

select 8 as x, number as c, bit_shift_left(8, number) as bit_shift_left from numbers("number"="5")
--------------

+------+------+----------------+
| x | c | bit_shift_left |
+------+------+----------------+
| 8 | 0 | 8 |
| 8 | 1 | 16 |
| 8 | 2 | 32 |
| 8 | 3 | 64 |
| 8 | 4 | 128 |
+------+------+----------------+
5 rows in set (0.04 sec)

对于 BIGINT 类型的最大值 9223372036854775807(即 BIGINT_MAX),进行一位左移的结果将得到 -2。

WITH tbl AS (
SELECT 9223372036854775807 AS BIGINT_MAX
)
SELECT BIGINT_MAX, bit_shift_left(BIGINT_MAX, 1)
FROM tbl
--------------

+---------------------+-------------------------------+
| BIGINT_MAX | bit_shift_left(BIGINT_MAX, 1) |
+---------------------+-------------------------------+
| 9223372036854775807 | -2 |
+---------------------+-------------------------------+
1 row in set (0.05 sec)

keywords

BITSHIFT, BITSHIFTLEFT