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 $order"; vs2010 创建PHP 为什么浏览不了 学习mysql存储过程 被挡在门口了…… 怎样把图标符号转换成图标 关于sendmail和Jmail的问题 关于PHP push的问题 Linux 下 gd 库的安装问题? 怎么解决啊 百思不得其解的问题 XML不是对某些浏览器不支持的吗 MediaWiki源码请教 本地网络的问题 url rewrite,可以禁止输入实际url访问的访问吗?
这里的and (1或and (0是指$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";