警告：mysql_num_rows（）期望参数1是资源，给定布尔值 [英] Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given

问题描述

下面是我的数据库表，我需要选择标题xyz如果类别是小说，为此我使用CASE条件但是我得到错误请任何人帮助我

below is my database table, I need to select title xyz if category is fiction, for this I am using CASE condition but I am gettin error please anyone help me

------------------------------------------
     title         |     category
                   |     
-----------------------------------------

    xyz                  fiction

    adapt                fiction

    adaxx                 fiction

    follow                journal

    your                   acadamic
--------------------------------------------

<br />
SELECT  CASE WHEN category = fiction THEN title LIKE '%xyz%' END FROM books<br />

它无法正常工作请帮助我。

Its not working please help me.

推荐答案

查询看起来很奇怪。您无法在SELECT子句中构建条件。例如，以下是有效的声明

The query looks very odd. You can't build conditions in SELECT clause. For example the following would be a valid statement

SELECT CASE WHEN category = 'fiction' THEN 'found' END 
FROM books
WHERE title LIKE '%xyz%'

另请注意，LIKE是一个可以在WHERE子句中使用的运算符，在其他地方并不多。

Also note that LIKE is an operator that can be used in WHERE clause, not much elsewhere.

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