Php 如何在特定列中获取值为null的记录？

我在一些项目中使用了

flourishlib

假设我有一个名为

categories（id，name，parent\u id）

的表，其中

parent\u id

是

categories

表的

外键

我正在使用
fRecordSet:：build（）
选择记录集。我想选择没有父项的记录。在MySQL中，这将是

select * from categories where parent_id is null

但是，我想使用
fRecordSet:：build
来实现这一点。我没有在文档中看到这样做的可能性，也没有在示例中看到这样做的可能性，而且，我也没有看到在方法中看到这样做的可能性。是否可以像上面显示的查询那样运行
fRecordSet:：build
过滤

供您参考，我想使用的方法如下：

/**
 * Creates an fRecordSet by specifying the class to create plus the where conditions and order by rules
 * 
 * The where conditions array can contain `key => value` entries in any of
 * the following formats:
 * 
 * {{{
 * 'column='                    => VALUE,                       // column = VALUE
 * 'column!'                    => VALUE                        // column <> VALUE
 * 'column!='                   => VALUE                        // column <> VALUE
 * 'column<>'                   => VALUE                        // column <> VALUE
 * 'column~'                    => VALUE                        // column LIKE '%VALUE%'
 * 'column^~'                   => VALUE                        // column LIKE 'VALUE%'
 * 'column$~'                   => VALUE                        // column LIKE '%VALUE'
 * 'column!~'                   => VALUE                        // column NOT LIKE '%VALUE%'
 * 'column<'                    => VALUE                        // column < VALUE
 * 'column<='                   => VALUE                        // column <= VALUE
 * 'column>'                    => VALUE                        // column > VALUE
 * 'column>='                   => VALUE                        // column >= VALUE
 * 'column=:'                   => 'other_column'               // column = other_column
 * 'column!:'                   => 'other_column'               // column <> other_column
 * 'column!=:'                  => 'other_column'               // column <> other_column
 * 'column<>:'                  => 'other_column'               // column <> other_column
 * 'column<:'                   => 'other_column'               // column < other_column
 * 'column<=:'                  => 'other_column'               // column <= other_column
 * 'column>:'                   => 'other_column'               // column > other_column
 * 'column>=:'                  => 'other_column'               // column >= other_column
 * 'column='                    => array(VALUE, VALUE2, ... )   // column IN (VALUE, VALUE2, ... )
 * 'column!'                    => array(VALUE, VALUE2, ... )   // column NOT IN (VALUE, VALUE2, ... )
 * 'column!='                   => array(VALUE, VALUE2, ... )   // column NOT IN (VALUE, VALUE2, ... )
 * 'column<>'                   => array(VALUE, VALUE2, ... )   // column NOT IN (VALUE, VALUE2, ... )
 * 'column~'                    => array(VALUE, VALUE2, ... )   // (column LIKE '%VALUE%' OR column LIKE '%VALUE2%' OR column ... )
 * 'column^~'                   => array(VALUE, VALUE2, ... )   // (column LIKE 'VALUE%' OR column LIKE 'VALUE2%' OR column ... )
 * 'column$~'                   => array(VALUE, VALUE2, ... )   // (column LIKE '%VALUE' OR column LIKE '%VALUE2' OR column ... )
 * 'column&~'                   => array(VALUE, VALUE2, ... )   // (column LIKE '%VALUE%' AND column LIKE '%VALUE2%' AND column ... )
 * 'column!~'                   => array(VALUE, VALUE2, ... )   // (column NOT LIKE '%VALUE%' AND column NOT LIKE '%VALUE2%' AND column ... )
 * 'column!|column2<|column3='  => array(VALUE, VALUE2, VALUE3) // (column <> '%VALUE%' OR column2 < '%VALUE2%' OR column3 = '%VALUE3%')
 * 'column|column2><'           => array(VALUE, VALUE2)         // WHEN VALUE === NULL: ((column2 IS NULL AND column = VALUE) OR (column2 IS NOT NULL AND column <= VALUE AND column2 >= VALUE))
 *                                                              // WHEN VALUE !== NULL: ((column <= VALUE AND column2 >= VALUE) OR (column >= VALUE AND column <= VALUE2))
 * 'column|column2|column3~'    => VALUE                        // (column LIKE '%VALUE%' OR column2 LIKE '%VALUE%' OR column3 LIKE '%VALUE%')
 * 'column|column2|column3~'    => array(VALUE, VALUE2, ... )   // ((column LIKE '%VALUE%' OR column2 LIKE '%VALUE%' OR column3 LIKE '%VALUE%') AND (column LIKE '%VALUE2%' OR column2 LIKE '%VALUE2%' OR column3 LIKE '%VALUE2%') AND ... )
 * }}}
 * 
 * When creating a condition in the form `column|column2|column3~`, if the
 * value for the condition is a single string that contains spaces, the
 * string will be parsed for search terms. The search term parsing will
 * handle quoted phrases and normal words and will strip punctuation and
 * stop words (such as "the" and "a").
 * 
 * The order bys array can contain `key => value` entries in any of the
 * following formats:
 * 
 * {{{
 * 'column'     => 'asc'      // 'first_name' => 'asc'
 * 'column'     => 'desc'     // 'last_name'  => 'desc'
 * 'expression' => 'asc'      // "CASE first_name WHEN 'smith' THEN 1 ELSE 2 END" => 'asc'
 * 'expression' => 'desc'     // "CASE first_name WHEN 'smith' THEN 1 ELSE 2 END" => 'desc'
 * }}}
 * 
 * The column in both the where conditions and order bys can be in any of
 * the formats:
 * 
 * {{{
 * 'column'                                                         // e.g. 'first_name'
 * 'current_table.column'                                           // e.g. 'users.first_name'
 * 'related_table.column'                                           // e.g. 'user_groups.name'
 * 'related_table{route}.column'                                    // e.g. 'user_groups{user_group_id}.name'
 * 'related_table=>once_removed_related_table.column'               // e.g. 'user_groups=>permissions.level'
 * 'related_table{route}=>once_removed_related_table.column'        // e.g. 'user_groups{user_group_id}=>permissions.level'
 * 'related_table=>once_removed_related_table{route}.column'        // e.g. 'user_groups=>permissions{read}.level'
 * 'related_table{route}=>once_removed_related_table{route}.column' // e.g. 'user_groups{user_group_id}=>permissions{read}.level'
 * 'column||other_column'                                           // e.g. 'first_name||last_name' - this concatenates the column values
 * }}}
 * 
 * In addition to using plain column names for where conditions, it is also
 * possible to pass an aggregate function wrapped around a column in place
 * of a column name, but only for certain comparison types. //Note that for
 * column comparisons, the function may be placed on either column or both.//
 * 
 * {{{
 * 'function(column)='   => VALUE,                       // function(column) = VALUE
 * 'function(column)!'   => VALUE                        // function(column) <> VALUE
 * 'function(column)!=   => VALUE                        // function(column) <> VALUE
 * 'function(column)<>'  => VALUE                        // function(column) <> VALUE
 * 'function(column)~'   => VALUE                        // function(column) LIKE '%VALUE%'
 * 'function(column)^~'  => VALUE                        // function(column) LIKE 'VALUE%'
 * 'function(column)$~'  => VALUE                        // function(column) LIKE '%VALUE'
 * 'function(column)!~'  => VALUE                        // function(column) NOT LIKE '%VALUE%'
 * 'function(column)<'   => VALUE                        // function(column) < VALUE
 * 'function(column)<='  => VALUE                        // function(column) <= VALUE
 * 'function(column)>'   => VALUE                        // function(column) > VALUE
 * 'function(column)>='  => VALUE                        // function(column) >= VALUE
 * 'function(column)=:'  => 'other_column'               // function(column) = other_column
 * 'function(column)!:'  => 'other_column'               // function(column) <> other_column
 * 'function(column)!=:' => 'other_column'               // function(column) <> other_column
 * 'function(column)<>:' => 'other_column'               // function(column) <> other_column
 * 'function(column)<:'  => 'other_column'               // function(column) < other_column
 * 'function(column)<=:' => 'other_column'               // function(column) <= other_column
 * 'function(column)>:'  => 'other_column'               // function(column) > other_column
 * 'function(column)>=:' => 'other_column'               // function(column) >= other_column
 * 'function(column)='   => array(VALUE, VALUE2, ... )   // function(column) IN (VALUE, VALUE2, ... )
 * 'function(column)!'   => array(VALUE, VALUE2, ... )   // function(column) NOT IN (VALUE, VALUE2, ... )
 * 'function(column)!='  => array(VALUE, VALUE2, ... )   // function(column) NOT IN (VALUE, VALUE2, ... )
 * 'function(column)<>'  => array(VALUE, VALUE2, ... )   // function(column) NOT IN (VALUE, VALUE2, ... )
 * }}}
 * 
 * The aggregate functions `AVG()`, `COUNT()`, `MAX()`, `MIN()` and
 * `SUM()` are supported across all database types.
 * 
 * Below is an example of using where conditions and order bys. Please note
 * that values should **not** be escaped for the database, but should just
 * be normal PHP values.
 * 
 * {{{
 * #!php
 * return fRecordSet::build(
 *     'User',
 *     array(
 *         'first_name='      => 'John',
 *         'status!'          => 'Inactive',
 *         'groups.group_id=' => 2
 *     ),
 *     array(
 *         'last_name'   => 'asc',
 *         'date_joined' => 'desc'
 *     )
 * );
 * }}}
 * 
 * @param  string  $class             The class to create the fRecordSet of
 * @param  array   $where_conditions  The `column => value` comparisons for the `WHERE` clause
 * @param  array   $order_bys         The `column => direction` values to use for the `ORDER BY` clause
 * @param  integer $limit             The number of records to fetch
 * @param  integer $page              The page offset to use when limiting records
 * @return fRecordSet  A set of fActiveRecord objects
 */
static public function build($class, $where_conditions=array(), $order_bys=array(), $limit=NULL, $page=NULL)
{
    fActiveRecord::validateClass($class);
    fActiveRecord::forceConfigure($class);

    $db     = fORMDatabase::retrieve($class, 'read');
    $schema = fORMSchema::retrieve($class);
    $table  = fORM::tablize($class);

    $params = array($db->escape("SELECT %r.* FROM :from_clause", $table));

    if ($where_conditions) {
        $having_conditions = fORMDatabase::splitHavingConditions($where_conditions);
    } else {
        $having_conditions = NULL;  
    }

    if ($where_conditions) {
        $params[0] .= ' WHERE ';
        $params = fORMDatabase::addWhereClause($db, $schema, $params, $table, $where_conditions);
    }

    $params[0] .= ' :group_by_clause ';

    if ($having_conditions) {
        $params[0] .= ' HAVING ';
        $params = fORMDatabase::addHavingClause($db, $schema, $params, $table, $having_conditions); 
    }

    // If no ordering is specified, order by the primary key
    if (!$order_bys) {
        $order_bys = array();
        foreach ($schema->getKeys($table, 'primary') as $pk_column) {
            $order_bys[$table . '.' . $pk_column] = 'ASC';  
        }
    }

    $params[0] .= ' ORDER BY ';
    $params = fORMDatabase::addOrderByClause($db, $schema, $params, $table, $order_bys);

    $params = fORMDatabase::injectFromAndGroupByClauses($db, $schema, $params, $table);

    // Add the limit clause and create a query to get the non-limited total
    $non_limited_count_sql = NULL;
    if ($limit !== NULL) {
        $pk_columns = array();
        foreach ($schema->getKeys($table, 'primary') as $pk_column) {
            $pk_columns[] = $table . '.' . $pk_column;  
        }

        $non_limited_count_sql = str_replace(
            $db->escape('SELECT %r.*', $table),
            $db->escape('SELECT %r', $pk_columns),
            $params[0]
        );
        $non_limited_count_sql = preg_replace('#\s+ORDER BY.*$#', '', $non_limited_count_sql);
        $non_limited_count_sql = $db->escape('SELECT count(*) FROM (' . $non_limited_count_sql . ') subquery', array_slice($params, 1));

        $params[0] .= ' LIMIT ' . $limit;

        if ($page !== NULL) {

            if (!is_numeric($page) || $page < 1) {
                $page = 1;
            }

            $params[0] .= ' OFFSET ' . (($page-1) * $limit);
        }
    } else {
        $page = 1;
    }

    return new fRecordSet($class, call_user_func_array($db->translatedQuery, $params), $non_limited_count_sql, $limit, $page);
}

/**
*通过指定要创建的类以及where条件和order by规则来创建fRecordSet
* 
*where conditions数组可以在以下任意一种类型中包含'key=>value'项：
*以下格式：
* 
* {{{
*'column='=>VALUE，//column=VALUE
*'列！'=>值//列值
*'列！='=>值//列值
*'列'=>值//列值
*“column~”=>VALUE//类似于“%VALUE%”的列
*'column^~'=>VALUE//类似于'VALUE%'的列
*'column$~'=>VALUE//类似于'%VALUE'的列
*'column！~'=>VALUE//column不象'%VALUE%'
*'列'=>值//列>值
*'列>='=>值//列>=值
*'列=：'=>'其他列'//列=其他列
*'列！：'=>'其他列'//列其他列
*'列！=：'=>'其他列'//列其他列
*'列：'=>'其他列'//列其他列
*'列：'=>'其他列'//列>其他列
*'列>=：'=>'其他列'//列>=其他列
*'column='=>array（VALUE，VALUE2，…）//中的列（VALUE，VALUE2，…）
*'column！'=>array（VALUE，VALUE2，…）//列不在（VALUE，VALUE2，…）
*'column！='=>array（VALUE，VALUE2，…）//列不在（VALUE，VALUE2，…）
*'column'=>array（VALUE，VALUE2，…）//列不在（VALUE，VALUE2，…）
*'column~'=>array（VALUE，VALUE2，…）/（类似于'%VALUE%'的列或类似于'%VALUE2%'的列或列…）
*'column^~'=>数组（值，值2，…）/（类似于'VALUE%'的列或类似于'VALUE2%'的列或列…）
*'column$~'=>数组（值，值2，…）/（类似于'%VALUE'的列或类似于'%VALUE2'的列或列…）
*'列&~'=>数组（值，值2，…）/（类似于'%VALUE%'的列和类似于'%VALUE2%'的列以及列…）
*'列！~'=>数组（值，值2，…）/（列不象'%VALUE%'和列不象'%VALUE2%'和列…）
*'column！| column2once_删除了_相关的_表。column'//例如'user_groups=>permissions.level'
*'related_table{route}=>once_remove_related_table.column'//例如'user_groups{user_group_id}=>permissions.level'
*'related_table=>once_remove_related_table{route}.column'//例如'user_groups=>permissions{read}.level'
*'related_table{route}=>once_remove_related_table{route}.column'//例如'user_groups{user_group_id}=>permissions{read}.level'
*“column | | other _column”//例如“first _name | | last _name”-这将连接列值
* }}}
* 
*除了对where条件使用普通列名外，它还
*可以在适当的位置传递环绕列的聚合函数
*列名称，但仅适用于某些比较类型//请注意，对于
*列比较时，函数可以放在任一列上，也可以同时放在两个列上//
* 
* {{{
*'函数（列）='=>值，//函数（列）=值
*“函数（列）！”=>值//函数（列）值
*'函数（列）！==>值//函数（列）值
*'函数（列）=>值//函数（列）值
*'function（column）~'=>VALUE//function（column）类似于'%VALUE%'
*'function（column）^~'=>VALUE//function（column）类似于'VALUE%'
*'function（column）$~'=>VALUE//function（column）类似于'%VALUE'
*“函数（列）！~”=>VALUE//function（列）与“%VALUE%”不同
*'函数（列）=>值//函数（列）>值
*'函数（列）>='=>值//函数（列）>=值
*'函数（列）=:'=>'其他列'//函数（列）=其他列
*'函数（列）！：'=>'其他列'//函数（列）其他列
*'函数（列）！=：'=>'其他列'//函数（列）其他列
*'函数（列）：'=>'其他列'//函数（列）其他列
*'函数（列）：'=>'其他列'//函数（列）>其他列
*'函数（列）>=：'=>'其他列'//函数（列）>=其他列
*'函数（列）='=>数组（值，值2，…）//函数（列）
select null = null

null

fRecordSet::build("Category", array("parent_id=" => null))

{"parent_id=": null}