MySql选择两个变量

Question

我有一个从1到1000的id表。如何从表中选择行并将结果插入到我声明的两个变量中？

有些事情是这样的：

Select from table1 where id = 1 or id = 27 into var1, var2

Answer 1

您可以这样做，但您需要确认以下两个限制：

1. 结果集必须只包含一行
2. 该行必须包含两列

见：

SELECT 'foo', 4 FROM DUAL INTO @a, @b;

SELECT @a, @b;
+------+------+
| @a   | @b   |
+------+------+
| foo  |    4 |
+------+------+

也有可能：

SELECT MIN(id), MAX(Population) FROM world.City INTO @min_id, @max_pop;

SELECT name, population FROM world.Country LIMIT 1 INTO @name, @pop;

Answer 2

SELECT
    @var1 := MAX(IF(id = 1, some_field, NULL)),
    @var2 := MAX(IF(id = 27, some_field, NULL))
FROM table
WHERE id IN (1,27);