来自PHP的MySQL查询

Question

我需要从PHP进行以下查询：

set @row:=-1;
SELECT * FROM `tablename`
INNER JOIN ( 
    SELECT `id` FROM ( 
        SELECT @row:=@row+1 AS rownum, `id` FROM ( 
            SELECT id FROM `tablename` ORDER BY `id` DESC 
        ) 
            AS sorted 
    ) as ranked WHERE rownum % 14 = 0 
) AS subset ON subset.id = `tablename`.id LIMIT 24;

在PHPMyAdmin中工作正常，但是“ set @ row = -1;”出现错误。 :(

提前致谢！

Answer 1

您可能试图在单个mysqli_query语句中使用这些语句。 这些是多个语句； 您需要在使用PHP代码时分别查询它们。

但是，您也可以使用CROSS JOIN将这两个查询转换为单个查询：

SELECT * FROM `tablename`
INNER JOIN ( 
    SELECT `id` FROM ( 
        SELECT @row:=@row+1 AS rownum, `id` FROM ( 
            SELECT id FROM `tablename` ORDER BY `id` DESC 
        ) AS sorted 
        CROSS JOIN (SELECT @row := -1) AS user_init_vars 
  /* shifted SET statement to the above line (remove the comment before using) */
    ) as ranked WHERE rownum % 14 = 0 
) AS subset ON subset.id = `tablename`.id LIMIT 24;