bitmap_and_not,bitmap_andnot
description
Syntax
BITMAP BITMAP_AND_NOT(BITMAP lhs, BITMAP rhs)
将两个bitmap进行与非操作并返回计算结果。
example
mysql> select bitmap_count(bitmap_and_not(bitmap_from_string('1,2,3'),bitmap_from_string('3,4,5'))) cnt;
+------+
| cnt |
+------+
| 2 |
+------+
mysql> select bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'),bitmap_from_string('3,4,5')));
+--------------------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'), bitmap_from_string('3,4,5'))) |
+--------------------------------------------------------------------------------------------+
| 1,2 |
+--------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)
mysql> select bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'),bitmap_empty())) ;
+-------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'), bitmap_empty())) |
+-------------------------------------------------------------------------------+
| 1,2,3 |
+-------------------------------------------------------------------------------+
mysql> select bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'),NULL));
+---------------------------------------------------------------------+
| bitmap_to_string(bitmap_and_not(bitmap_from_string('1,2,3'), NULL)) |
+---------------------------------------------------------------------+
| NULL |
+---------------------------------------------------------------------+keywords
BITMAP_AND_NOT,BITMAP_ANDNOT,BITMAP