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

1. select 8 as x, number as c, bit_shift_left(8, number) as bit_shift_left from numbers("number"="5")
2. --------------

4. +------+------+----------------+
5. | x    | c    | bit_shift_left |
6. +------+------+----------------+
7. |    8 |    0 |              8 |
8. |    8 |    1 |             16 |
9. |    8 |    2 |             32 |
10. |    8 |    3 |             64 |
11. |    8 |    4 |            128 |
12. +------+------+----------------+
13. 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。

1. WITH tbl AS (
2. SELECT 9223372036854775807 AS BIGINT_MAX
3. )
4. SELECT BIGINT_MAX, bit_shift_left(BIGINT_MAX, 1)
5. FROM tbl
6. --------------

8. +---------------------+-------------------------------+
9. | BIGINT_MAX          | bit_shift_left(BIGINT_MAX, 1) |
10. +---------------------+-------------------------------+
11. | 9223372036854775807 |                            -2 |
12. +---------------------+-------------------------------+
13. 1 row in set (0.05 sec)

keywords

1. BITSHIFT, BITSHIFTLEFT