使用 $this->db->count_all_results() 时出错； as 在布尔值上调用成员函数 num_rows()答案

【问题标题】：Error for using $this->db->count_all_results(); as Call to a member function num_rows() on boolean使用 $this->db->count_all_results() 时出错； as 在布尔值上调用成员函数 num_rows()
【发布时间】：2020-09-11 08:31:44
【问题描述】：

在我的模型中，我有一个根据 category_id 获取产品数量的函数

public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    if ($category_id) {
        $this->db->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $this->db->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $this->db->where('brand', $brand_id);
    }
    $this->db->where('hide_pos !=', 1);
    $this->db->from('products');
    return $this->db->count_all_results();
}

我收到错误

An uncaught Exception was encountered

Type: Error

Message: Call to a member function num_rows() on boolean

Filename: /var/www/html/projects/demo/system/database/DB_query_builder.php

Line Number: 1429

Backtrace:

File: /var/www/html/projects/demo/app/models/admin/Pos_model.php
Line: 158
Function: count_all_results

错误是什么问题。谢谢

【问题讨论】：

标签： php codeigniter codeigniter-3

【解决方案1】：

如果我认为你正在使用 Codeigniter 4。如果这是真的。请在下面使用它。我认为它会帮助你解决这个问题。如果您要扩展到 Codeigniter 核心模型，则不需要 $this->db。只是

扩展到 Codeigniter 核心模型，使用

public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    $query = $this->table('products'); // self::table('products')

    if ($category_id) {
        $query = $query->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $query = $query->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $query = $query->where('brand', $brand_id);
    }
    $query = $query->where('hide_pos !=', 1);
    
    return $query->countAllResults();
}

如果不扩展到 Codeigniter Core 模型，请使用


public function __construct()
{
    $this->db = db_connect();
}
public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    $query = $this->db->table('products');

    if ($category_id) {
        $query = $query->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $query = $query->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $query = $query->where('brand', $brand_id);
    }
    $query = $query->where('hide_pos !=', 1);
    
    return $query->countAllResults();
}

如果您按照您所说的使用 codeigniter 3，请使用此


public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    $query = $this->db->from('products');

    if ($category_id) {
        $query = $query->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $query = $query->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $query = $query->where('brand', $brand_id);
    }
    $query = $query->where('hide_pos !=', 1);
    
    return $query->count_all_results();
}

或

public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    $query = $this->db->from('products');

    if ($category_id) {
        $query = $query->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $query = $query->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $query = $query->where('brand', $brand_id);
    }
    $query = $query->where('hide_pos !=', 1)->get();
    
    return $query->num_row();
}

如果不引起我的注意，我希望这会有所帮助

【讨论】：

感谢您的回复，但我使用的是 ci3
我已经编辑了我的帖子，所以请检查它是否有 codeigniter 3

【解决方案2】：

为什么不用$this->db->num_rows()而不是$this->db->count_all_results()，结果更准确，我正在重写你的函数，请试试这个。

public function products_count($category_id, $subcategory_id = null, $brand_id = null)
{
    $this->db->from('products');
    if ($category_id) {
        $this->db->where('category_id', $category_id);
    }
    if ($subcategory_id) {
        $this->db->where('subcategory_id', $subcategory_id);
    }
    if ($brand_id) {
        $this->db->where('brand', $brand_id);
    }
    $this->db->where('hide_pos !=', 1);
    $this->db->get();
    return $this->db->num_rows();
}

如果您想使用自己的代码，只需将$this->db->from('products') 放在顶部，我希望这也可以。

【讨论】：