将多个删除查询修改为尽可能少的更新查询？

Posted 2023-04-15

【中文标题】将多个删除查询修改为尽可能少的更新查询？

【英文标题】：Modify multiple delete queries into as little update queries as possible?

【发布时间】：2012-11-27 10:48:28

【问题描述】：

我们目前有这个代码sn-p：

$this->db->where('id', $id)->delete($this->table);
$this->db->where('product_id', $id)->delete($this->clink);
$this->db->where('product_id', $id)->delete($this->tlink);

$variants = $this->db->select('id')->from($this->vlink)->where('product_id', $id)->get();
if ($variants->num_rows() !== 0) 

    //turns array(array('id' => 1), array('id' => 2)) into array(1,2)
    $variants = $variants->result_array();
    foreach ($variants as &$v) 
        $v = $v['id'];
    

    $this->db->where('product_id', $id)->delete($this->vlink);
    $this->db->where_in('variant_id', $variants)->delete('cart_variant_values');
    $this->db->where_in('variant_id', $variants)->delete('cart_variant_images');
    $this->db->where_in('variant_id', $variants)->delete('cart_variant_documents');

翻译成这样：

delete from $this->table where id = $id
delete from $this->clink where product_id = $id
delete from $this->tlink where product_id = $id

$variants = select id from $this->vlink where product_id = $id //e.g. (1,2) 

delete from $this->vlink where product_id = $id
delete from cart_variant_values where variant_id in $variants
delete from cart_variant_images where variant_id in $variants
delete from cart_variant_documents where variant_id in $variants

现在我需要修改代码，而不是删除所有行，而是在所有行上设置end_date 列。

我知道我可以修改它。保留相同数量的查询，但我希望作为更新而不是删除，我可以将其缩小为更少的查询？

【参考方案1】：

如果您担心删除查询的数量，您可以使用多表删除查询，通过它可以将其减少为单个查询DELETE Syntax

UPDATE也可以实现多表查询UPDATE Syntax