支持操作符

Halo 数据库在 MySQL 兼容模式下支持以下操作符。

比较运算符

支持 =、<> / !=、IS NULL / IS NOT NULL、BETWEEN ... AND 等比较运算符。

mysql> SELECT 1=0, '2'=2, 2=2;
+----------+----------+----------+
| ?column? | ?column? | ?column? |
+----------+----------+----------+
|        0 |        1 |        1 |
+----------+----------+----------+

mysql> SELECT NULL IS NULL, 10 IS NOT NULL;
+----------+----------+
| ?column? | ?column? |
+----------+----------+
|        1 |        1 |
+----------+----------+

mysql> SELECT 4 BETWEEN 4 AND 6, 12 BETWEEN 9 AND 10;
+----------+----------+
| ?column? | ?column? |
+----------+----------+
|        1 |        0 |
+----------+----------+

逻辑运算符

支持 AND、OR、NOT、XOR 等逻辑运算符。

mysql> SELECT 1 XOR 1, 0 XOR 0, 1 XOR 0;
+----------+----------+----------+
| ?column? | ?column? | ?column? |
+----------+----------+----------+
|        0 |        0 |        1 |
+----------+----------+----------+

位运算符

支持 |（位或）、&（位与）、^（位异或）、<<（左移）、>>（右移）等位运算符。

mysql> SELECT 10|15 AS bit_or, 10&15 AS bit_and, 10^15 AS bit_xor;
+--------+---------+---------+
| bit_or | bit_and | bit_xor |
+--------+---------+---------+
|     15 |      10 |       5 |
+--------+---------+---------+

mysql> SELECT 1<<2, 16>>2;
+----------+----------+
| ?column? | ?column? |
+----------+----------+
|        4 |        4 |
+----------+----------+