php tp5遍历求和,thinkphp5提供withCount()方法封装withSum()和调用

针对hasMany()进行封装，hasOne()等类似，假如有两张表，user(用户表)，和order(订单表)，我们要做的是统计每个用户订单里的fee字段的总和。

Query.php 添加//统计求和

public function withSum($relation, $subQuery = true, $sum='sum')

{

if (!$subQuery) {

$this->options['with_sum'] = $relation;

} else {

$relations = is_string($relation) ? explode(',', $relation) : $relation;

if (!isset($this->options['field'])) {

$this->field('*');

}

foreach ($relations as $key => $relation) {

$closure = false;

if ($relation instanceof \Closure) {

$closure = $relation;

$relation = $key;

}

$relation = Loader::parseName($relation, 1, false);

$count = '(' . $this->model->$relation()->getRelationSumQuery($closure, $sum) . ')';

$this->field([$count => Loader::parseName($relation) . '_sum']);

}

}

return $this;

}

HasMany.php 添加：public function getRelationSumQuery($closure, $sum)

{

if ($closure) {

call_user_func_array($closure, [ & $this->query]);

}

$localKey = $this->localKey ?: $this->parent->getPk();

return $this->query->whereExp($this->foreignKey, '=' . $this->parent->getTable() . '.' . $localKey)->fetchSql()->sum($sum);

}

调用方法：$data = model('user')->withSum('order', 'fee')->select();

widthSum('order')，这里的order指的是模型里针对hasMany添加的一个方法。public function order()

{

return $this->hasMany('Order');

}