[英]Grouping WHERE clauses in Codeigniter
我想在 Codeigniter 中使用 Active Record 生成以下 SQL 代碼:
WHERE name != 'Joe' AND (age < 69 OR id > 50)
做以下似乎盡我所能,我不知道如何將它們分組
$this->db->select()->from('users')->where('name !=', 'Joe')->where('age <', 69)->or_where('id <', $id);
有任何想法嗎? 我的 SQL 查詢太復雜了,所以我不想用傳統的 SQL 重寫所有內容。
更新
我的 SQL 代碼是根據傳遞給模型方法的某些參數的值動態生成的。 無法使用括號的問題會導致問題,因為運算符的優先級是AND
在OR
之前首先進行評估。
*這是我的活動記錄代碼的一部分,在它之前和之后還有一些其他代碼:
... some $this->db->where() ...
... some $this->db->where() ...
if($price_range) {
$price_array = explode('.', $price_range);
for($i = 0; $i < count($price_array); $i++) {
if($i == 0) {
$this->db->where('places.price_range', $price_array[$i]);
} else {
$this->db->or_where('places.price_range', $price_array[$i]);
}
}
}
... some $this->db->where() ...
... some $this->db->where() ...
問題出現是因為我正在使用$this->db->or_where()
,它引入了一個OR
子句,該子句將運算符優先級置於混亂狀態,而無法使用( )
來更改順序。
** 有沒有辦法解決這個問題? **
在 Codeigniter 3.0.3 中,您可以像這樣簡單地進行操作:
$this->db->select()
->from('users')
->where('name !=', 'Joe')
->group_start() // Open bracket
->where('age <', 69)
->or_where('id <', $id)
->group_end(); // Close bracket
也許它可以幫助
您可以使用一根大字符串。
$this->db->select()->from('users')->where("name != 'Joe' AND (age < 69 OR id > 50) ");
默認情況下,where 子句的分組不在 CI 中。 您必須擴展核心並添加能力。 我通過以下方式做到了這一點:
class MY_DB_mysql_driver extends CI_DB_mysql_driver
{
public function __construct($params)
{
parent::__construct($params);
}
/**
* This function will allow you to do complex group where clauses in to c and (a AND b) or ( d and e)
* This function is needed as else the where clause will append an automatic AND in front of each where Thus if you wanted to do something
* like a AND ((b AND c) OR (d AND e)) you won't be able to as the where would insert it as a AND (AND (b...)) which is incorrect.
* Usage: start_group_where(key,value)->where(key,value)->close_group_where() or complex queries like
* open_bracket()->start_group_where(key,value)->where(key,value)->close_group_where()
* ->start_group_where(key,value,'','OR')->close_group_where()->close_bracket() would produce AND ((a AND b) OR (d))
* @param $key mixed the table columns prefix.columnname
* @param $value mixed the value of the key
* @param $escape string any escape as per CI
* @param $type the TYPE of query. By default it is set to 'AND'
* @return db object.
*/
function start_group_where($key,$value=NULL,$escape,$type="AND")
{
$this->open_bracket($type);
return parent::_where($key, $value,'',$escape);
}
/**
* Strictly used to have a consistent close function as the start_group_where. This essentially callse the close_bracket() function.
*/
function close_group_where()
{
return $this->close_bracket();
}
/**
* Allows to place a simple ( in a query and prepend it with the $type if needed.
* @param $type string add a ( to a query and prepend it with type. Default is $type.
* @param $return db object.
*/
function open_bracket($type="AND")
{
$this->ar_where[] = $type . " (";
return $this;
}
/**
* Allows to place a simple ) to a query.
*/
function close_bracket()
{
$this->ar_where[] = ")";
return $this;
}
}
用法:
group_where_start(key,value)->where(key,value)->group_where_close()
或者
復雜的查詢,如
open_bracket()->start_group_where(key,value)->where(key,value)->close_group_where()->start_group_where(key,value,'','OR')->close_group_where()->close_bracket() would produce AND ((a AND b) OR (d))
CI3有你需要的一切!
$this->db->select('*')->from('my_table')
->group_start()
->where('a', 'a')
->or_group_start()
->where('b', 'b')
->where('c', 'c')
->group_end()
->group_end()
->where('d', 'd')
->get();
https://www.codeigniter.com/userguide3/database/query_builder.html#query-grouping
我所做的是在 where 之后復制 and 子句,這實際上與長字符串選擇相同。
$this->db->select()
->from('users')
->where('name !=', 'Joe')
->where('age <', 69)
->or_where('id <', $id)
->where('name !=', 'Joe');
一個大的字符串方式可能更好。
解決了。 動態生成 SQL 查詢並將其插入$this->db->where()
。 謝謝你們!
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