BIT_OR(expr) [over_clause]Returns the bitwise OR of all bits in expr. The calculation is performed with 64-bit (BIGINT) precision. It is an aggregate function, and so can be used with the GROUP BY clause.
If no rows match, BIT_OR will return a value with all bits set to 0. NULL values have no effect on the result unless all results are NULL, which is treated as no match.
From MariaDB 10.2.0, BIT_OR can be used as a window function with the addition of the over_clause.
CREATE TABLE vals (x INT);
INSERT INTO vals VALUES(111),(110),(100);
SELECT BIT_AND(x), BIT_OR(x), BIT_XOR(x) FROM vals;
+------------+-----------+------------+
| BIT_AND(x) | BIT_OR(x) | BIT_XOR(x) |
+------------+-----------+------------+
| 100 | 111 | 101 |
+------------+-----------+------------+As an aggregate function:
CREATE TABLE vals2 (category VARCHAR(1), x INT);
INSERT INTO vals2 VALUES
('a',111),('a',110),('a',100),
('b','000'),('b',001),('b',011);
SELECT category, BIT_AND(x), BIT_OR(x), BIT_XOR(x)
FROM vals GROUP BY category;
+----------+------------+-----------+------------+
| category | BIT_AND(x) | BIT_OR(x) | BIT_XOR(x) |
+----------+------------+-----------+------------+
| a | 100 | 111 | 101 |
| b | 0 | 11 | 10 |
+----------+------------+-----------+------------+No match:
SELECT BIT_OR(NULL);
+--------------+
| BIT_OR(NULL) |
+--------------+
| 0 |
+--------------+