求一个SQL查询语句:select * from Table wher A B C D
select * from Table wher A and B and C and D
其中,A,B,C,D为条件。应该怎样构造啊?
是不是要先判断a,b,c,d中,只要有一个不为空,则“where”
那AND呢?》
[解决办法]
判断非空,拼sql字符串.一般先加 where 1=1 ,不会出现where and A了
[解决办法]
hookee() 正解
[解决办法]
hookee() 正解
where 1=1 和 where 1 != 1 在sql中会经常用到
1=1 为后面加东西做好铺垫,1 != 1 得到表的结构
[解决办法]
$aWhere[] = " 1=1 ";
if(!empty($A))
$aWhere[] = $A;
if(!emtpy($B))
$aWhere[] = $B;
if(!empty($C))
$aWhere[] = $C;
if(!empty($D))
$aWhere[] = $D;
$sWhere = join( ' and ', $aWhere);
$sSql = "select * from tbl where $sWhere order by id desc ";
[解决办法]
$condition = " ";
$link_symbol = " ";
if($a)
{
$condition .= "$link_symbol $a ";
$link_symbol = "and ";
}
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