Laravel 模型使用软删除-左连接查询-表起别名示例

2020-10-20 10:57:33 浏览数 (1)

事情是这样的,有天写了一个左连接查询,由于表名太长,所以分别给起个别名,代码如下:

代码语言:javascript复制
public function detail()
{
  $result = TakeOrderModel::query()
    - from('take_order as order')
    - leftJoin('take_order_detail as detail', 'order.id', '=', 'detail.take_order_id')
    - get();
  dd($result);
}

执行后,报错 Column not found: 1054 Unknown column take_order.delete_time。

查看解决办法的,直接看底部

SQL:

代码语言:javascript复制
select * from take_order as order
left join take_order_detail as detail
on order.take_order_id = detail.take_order_id
where take_order.delete_time is null

显而易见:软删除查询条件的表名是全名,所以报错了。

分析

软删除作用域 SoftDeletingScope 源码:

代码语言:javascript复制
/**
 * Apply the scope to a given Eloquent query builder.
 *
 * @param IlluminateDatabaseEloquentBuilder $builder
 * @param IlluminateDatabaseEloquentModel $model
 * @return void
 */
public function apply(Builder $builder, Model $model)
{
  $builder- whereNull($model- getQualifiedDeletedAtColumn());
}

查看 getQualifiedDeletedAtColumn 源码:

代码语言:javascript复制
/**
 * Get the fully qualified "deleted at" column.
 *
 * @return string
 */
public function getQualifiedDeletedAtColumn()
{
  return $this- qualifyColumn($this- getDeletedAtColumn());
}

查看 qualifyColumn 源码:

代码语言:javascript复制
/**
 * Qualify the given column name by the model's table.
 *
 * @param string $column
 * @return string
 */
public function qualifyColumn($column)
{
  return $this- model- qualifyColumn($column);
}

查看 qualifyColumn 源码:

代码语言:javascript复制
/**
 * Qualify the given column name by the model's table.
 *
 * @param string $column
 * @return string
 */
public function qualifyColumn($column)
{
  if (Str::contains($column, '.')) {
    return $column;
  }

  return $this- getTable().'.'.$column;
}

以上可知: this- getTable().’.’.column 即为软删除条件的字段名。

解决办法

代码改成下面这样,加一行 setTable 设置表名,就可以了。

代码语言:javascript复制
$result = (new TakeOrderModel())
    - setTable('order')
    - from('take_order as order')
    - leftJoin('take_order_detail as detail', 'order.take_order_id', '=', 'detail.take_order_id')
    - get();

因为写代码时要指定具体的查询 columns ,有时表名真的太长,看着很不舒服,所以有此尝试。嗯,9 点了,下班。

以上这篇Laravel 模型使用软删除-左连接查询-表起别名示例就是小编分享给大家的全部内容了,希望能给大家一个参考。

0 人点赞