PHP编程：PHP+Mysql实现多关键字与多字段生成SQL语句的函数

$keyword="1 2 3";
echo $sql=search($keyword,"enter_gongyin_pic","a+b+c"); //函数生成,没有LIMIT,没有ORDER BY

SELECT * FROM `enter_gongyin_pic` WHERE `a` LIKE '%1%' OR `a` LIKE '%2%' OR `a` LIKE '%3%' OR `b` LIKE '%1%' OR `b` LIKE '%2%' OR `b` LIKE '%3%' OR `c` LIKE '%1%' OR `c` LIKE '%2%' OR `c` LIKE '%3%'

function search($keyword,$table,$field)?
{?
//========================================================?
?
//形参说明：?
//keyword为关键字,如“北京首都 方向 火车”.带有空格或者不带?
//table为表名,如enter_gongyin_pic.?
//field为字段组合,如查找一个字段就写好 name??
//如查找两个以上就用 name+picdir?
//========================================================?
//首先确定field?
$new_field=explode("+",$field); //按+剥离?
$field_count=count($new_field); //得到的结果数量?
?
?
$newstring=explode(" ",$keyword); //按空格剥离?
$newstring2=array();?
?? //把字符串去掉没有用的空格叔祖元素?
?? $i=0;?
?? foreach ($newstring as $key => $value) {?
?? if($value!="")?
?? {?
?? $newstring2[$i]=$value;?
?? $i++;?
?? }?
?? }?
//把字符串去掉没有用的空格叔祖元素,?
?????????
$result_count=count($newstring2); //得到的结果数量?
?
//下面生成SQL语句?
?
?
//********************** if($field_count==1) //找1个字段 START ****************************?
if($field_count==1) //找1个字段?
{?
if($result_count==1) //判断如果是一个关键段?
?? {?
?? $newstring_search=$newstring2[0];?
$sql="SELECT *??
FROM `$table`??
WHERE `".$new_field[0]."` LIKE '%$newstring_search%'";?
?? }?
??????
?? if($result_count>1) //判断如果是多个关键段?
?? {?
?
$sql="SELECT *??
FROM `$table`??
WHERE ";?
$sql_add="";?
foreach ($newstring2 as $key => $value)?
{?
? if($key==0)?
?? {?
?? $sql_add=$sql_add."`".$new_field[0]."` LIKE '%".$value."%'";?
?? }?
?? else?
?? {?
?? $sql_add=$sql_add." OR `".$new_field[0]."` LIKE '%".$value."%'";?
?????
??????? }?
?????????
????????? }?
???
$sql=$sql.$sql_add;?
}?
?
}?
?
//********************** if($field_count==1) //找1个字段 END ****************************?
?
?
//********************** if($field_count>1) //找多个字段 START ****************************?
if($field_count>1) //找多个字段,这个时候$new_field是一个数组.拥有多个字段?
{?
if($result_count==1) //判断如果是一个关键段?
{?
??????? $newstring_search=$newstring2[0]; //$newstring_search是关键字?
??????? $sql="SELECT *??
??????? FROM `$table`??
??????? WHERE ";?
??????? $sql_add="";//新增加字段?
??????? foreach ($new_field as $key => $value)?
??????? {?
??????????????????????? if($key==0)?
??????????????????????? {?
??????????????????????? $sql_add=$sql_add."`".$value."` LIKE '%".$newstring_search."%'";?
??????????????????????? }?
??????????????????????? else?
??????????????????????? {?
??????????????????????? $sql_add=$sql_add." OR `".$value."` LIKE '%".$newstring_search."%'";?
??????????????????????? }?
??????? }?
??????? $sql=$sql.$sql_add;?
}?
if($result_count>1) //判断如果是多个关键段(多个关键字)==========================?
{?
$sql="SELECT *??
FROM `$table`??
WHERE ";?
$sql_add="";//新增加字段?
foreach ($new_field as $key => $value)?
{?
? if($key==0) //遇到$new_field[0]时候 例：`a` LIKE '%1%' OR `a` LIKE '%2%' OR `a` LIKE '%3%'?
?? { //嵌套foreach?
???? foreach ($newstring2 as $key2 => $value2)?
????? {?
????????????????? if($key2==0)?
?????????????????? {?
??????????????????????? $sql_add=$sql_add."`".$value."` LIKE '%".$value2."%'";?
?????????????????? }?
?????????????????? else?
?????????????????? {?
?????????????????? $sql_add=$sql_add." OR `".$value."` LIKE '%".$value2."%'";?
?????????????????? }?
??????? }?
??? //嵌套foreach?
?? }?
?? else??
?? //(如果是多字段的比如查name+picdir表)开始FOREACH连续循环,每次执行ELSE $new_field[1] $new_field[2] $new_field[3].?
?? //对应的值为$value?
? {?
?? //嵌套foreach(多字段与多关键字)?
?? foreach ($newstring2 as $key2 => $value2)?
????? {?
????????????????? if($key2==0)?
?????????????????? {?
??????????????????????? $sql_add=$sql_add." OR `".$value."` LIKE '%".$value2."%'";?
?????????????????? }?
?????????????????? else?
?????????????????? {?
?????????????????? $sql_add=$sql_add." OR `".$value."` LIKE '%".$value2."%'";?
?????????????????? }?
?????????? }?
?? //嵌套foreach?
?? }?
?????????
}//foreach ($new_field as $key => $value)结束?
$sql=$sql.$sql_add;?
}//if($result_count>1)结束?
}//if($field_count>1) 结束?
//********************** if($field_count>1) //找多个字段 END ****************************?
return $sql;?
}