这个条件1 AND ( 0 OR 条件2)逻辑运算怎么理解? 1and$b需要两个条件都成立1or$b因为已经判断前面是1成立了,后面的就不判断了0or$b前面是o不成立,所以继续判断$b是否成立。 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 谢谢楼上的回复,我再请教一下:这里的and (1或and (0是指$a的运算结果吗?有网友说不是,这是辅助条件,不是任何运算的结果值,我都看糊涂了,不知道正确答案是什么。还有,上面说的当条件为OR时加0才不会影响结果集是不是就是说:1or$b因为已经判断前面是1成立了,后面的就不判断了因为前面是1,所以就不会判断后面的条件了,所以就影响到后面的结果集,是这个意思吗?还望再予指点一下,谢谢。 要加的,不加就会出现错误,请看如下查询语句:$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,"." g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief "." FROM " .$ecs->table('goods'). " AS g"." WHERE g.is_delete = 0 AND g.is_alone_sale = 1"." AND ( 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where." ORDER BY $sort $order";如果这里不写上AND ( 1(即去掉1,那运行时就会出错,我测试过多次的确必须要写。 $categories . $keywords . $brand . $min_price . $max_price . $intro 你是说这些有可能会空是吧?$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,"." g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief "." FROM " .$ecs->table('goods'). " AS g"." WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where." ORDER BY $sort $order";这样不行? $sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,"." g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief "." FROM " .$ecs->table('goods'). " AS g"." WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where." ORDER BY $sort $order";这样错误的! 你的$categories . $keywords . $brand . $min_price . $max_price . $intro是什么东西啊?$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,"." g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief "." FROM " .$ecs->table('goods'). " AS g"." WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro .$tag_where." ORDER BY $sort $order"; 前缀不同可以恢复数据么 静态缓存 开发了一个BUG跟踪管理软件,开放源代码,欢迎大家下载试用 php运行效率问题 急救!!!PHP file_get_contents了一个页面!但是不想要那些HTML代码 在 PHP 中,按用户的权限登陆进入不同的页面 碟影论坛诚召php+mysql高手!待遇从优,可商量!急! 一个不错的网站,进来看一下吧! 我想用正则调取天气网中一段代码,老是获取不到! SOS: 请教怎么在百度统计里标志受访页面是微信打开? 本地网络的问题 url rewrite,可以禁止输入实际url访问的访问吗?
这里的and (1或and (0是指$a的运算结果吗?有网友说不是,这是辅助条件,不是任何运算的结果值,我都看糊涂了,不知道正确答案是什么。还有,上面说的当条件为OR时加0才不会影响结果集是不是就是说:
1or$b因为已经判断前面是1成立了,后面的就不判断了因为前面是1,所以就不会判断后面的条件了,所以就影响到后面的结果集,是这个意思吗?还望再予指点一下,谢谢。
$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,".
" g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief ".
" FROM " .$ecs->table('goods'). " AS g".
" WHERE g.is_delete = 0 AND g.is_alone_sale = 1".
" AND ( 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where.
" ORDER BY $sort $order";如果这里不写上AND ( 1(即去掉1,那运行时就会出错,我测试过多次的确必须要写。
你是说这些有可能会空是吧?$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,".
" g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief ".
" FROM " .$ecs->table('goods'). " AS g".
" WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where.
" ORDER BY $sort $order";
这样不行?
" g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief ".
" FROM " .$ecs->table('goods'). " AS g".
" WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro ." ) ".$tag_where.
" ORDER BY $sort $order";这样错误的!
$sql = "SELECT g.goods_id, g.goods_name, g.et_price, g.shop_price, g.promote_price,".
" g.promote_start, g.promote_end, g.goods_thumb, g.goods_img, g.goods_brief ".
" FROM " .$ecs->table('goods'). " AS g".
" WHERE g.is_delete = 0 AND g.is_alone_sale = 1 " . $categories . $keywords . $brand . $min_price . $max_price . $intro .$tag_where.
" ORDER BY $sort $order";