mysql - 选择语法 - 是 "something = (' this' or 'that' or 'other' )"ok to do?

Question

我正在使用 MySQL v5.5.27。我通常会这样写这个 SELECT 语句:

SELECT DISTINCT * 
FROM table 
WHERE something = 'this' 
    OR something = 'that' 
    OR something = 'other' 
    AND thingamajig = 'one' 
    OR thingamajig = 'two'

但是这个 SELECT 语句会提供完全相同的结果吗？

SELECT DISTINCT * 
FROM table 
WHERE something = ('this' OR 'that' OR 'other') 
    AND thingamajig = ('one' OR 'two')

我试过运行它并且它似乎正在运行。只是想确保第二种做事方式不会以我无法想到的某种方式返回错误数据。

感谢您的任何见解和帮助!

Answer 1

我建议使用括号来清楚地对搜索条件的顺序进行分组。

你的第二个 SELECT 语句比你的第一个更清晰。

SELECT DISTINCT * 
FROM table 
WHERE something = ('this' OR 'that' OR 'other') 
AND thingamajig = ('one' OR 'two')

请记住，当您有多个值时，您也可以使用 IN 运算符:

SELECT DISTINCT * 
FROM table 
WHERE something IN ('this', 'that', 'other') 
AND thingamajig IN ('one', 'two')

此外，使用 IN 运算符 performs much faster而不是使用 OR。