Question

我得到了以下查询。这应该返回一行，但它不会。

不幸的是没有。

当我删除最后一个连接子句时：

LEFT JOIN `serene_pagecontent` ON `serene_pageorder`.`pageorder_id` = `serene_pagecontent`.`pagecontent_link`

我确实得到了一个结果。但是当添加时它并没有。据我所知，在加入之前添加LEFT应该会提供结果，即使其中一个字段丢失了。

SELECT * FROM `serene_page`
LEFT JOIN `serene_pageoptions` ON `serene_page`.`page_id` = `serene_pageoptions`.`pageoptions_link`
LEFT JOIN `serene_pagetitle` ON `serene_page`.`page_id` = `serene_pagetitle`.`pagetitle_link`
LEFT JOIN `serene_pageorder` ON `serene_page`.`page_id` = `serene_pageorder`.`pageorder_link`
LEFT JOIN `serene_pagecontent` ON `serene_pageorder`.`pageorder_id` = `serene_pagecontent`.`pagecontent_link`
WHERE `page_id` = 34 AND `pageoptions_language` = 'NL' AND `pagetitle_language` = 'NL' AND `pagecontent_language` = 'NL'

任何人都可以告诉我我错过了什么。

修改

WHERE `serene_page`.`page_id` = 34 
  AND serene_pageoptions`.`pageoptions_language` = 'NL' 
  AND serene_pagetitle`.`pagetitle_language` = 'NL' 
  AND serene_pagecontent`.`pagecontent_language` = 'NL'

编辑解决方案：解决方案＆＃34; juergen d＆＃34;

     SELECT * FROM `serene_page`

     LEFT JOIN `serene_pageoptions` ON `serene_page`.`page_id` =`serene_pageoptions`.`pageoptions_link` AND
 `serene_pageoptions`.`pageoptions_language` = 'NL'       
  LEFT JOIN `serene_pagetitle` ON `serene_page`.`page_id` = `serene_pagetitle`.`pagetitle_link` AND
 `serene_pagetitle`.`pagetitle_language` = 'NL'     

     LEFT JOIN `serene_pageorder` ON `serene_page`.`page_id` = `serene_pageorder`.`pageorder_link` 


     LEFT JOIN `serene_pagecontent` ON `serene_pageorder`.`pageorder_id` =
 `serene_pagecontent`.`pagecontent_link` AND
 `serene_pagecontent`.`pagecontent_language` = 'NL'

     WHERE `serene_page`.`page_id` = 34

我不知道如果没有，我必须添加子条款它会变成正常的JOINS。谢谢！

Answer 1

如果你sourceIMG.addEventListener('click', function() { $.get('https://newsapi.org/v1/articles?source=' + this.id + '&sortBy=latest&apiKey=APIKEYHERE', function(data, status) { console.log(data); latestArticles = data.articles; for (i = 0; i < latestArticles.length; i++) { //New Article var newArticle = document.createElement("DIV"); newArticle.id = "article"; newArticle.className += "article"; //Title //Create an h1 Element var header = document.createElement("H1"); //Create the text entry for the H1 var title = document.createTextNode(latestArticles[i].title); //Append the text to the h1 Element header.appendChild(title); //Append the h1 element to the Div 'article' newArticle.appendChild(header); //Author var para = document.createElement("P"); var author = document.createTextNode(latestArticles[i].author); para.appendChild(author); newArticle.appendChild(para); //Description var description = document.createElement("H4"); var desc = document.createTextNode(latestArticles[i].description); description.appendChild(desc); newArticle.appendChild(description); //Image var image = document.createElement("IMG"); image.src = latestArticles[i].urlToImage; image.className += "articleImg"; newArticle.appendChild(image); //Url link //Create a href element var a = document.createElement('a'); var link = document.createElement('p'); var innerLink = document.createTextNode('Read the full story '); link.appendChild(innerLink); a.setAttribute("href", latestArticles[i].url); a.innerHTML = "here."; link.appendChild(a); newArticle.appendChild(link); //Append the Div 'article' to the outer div 'articles' document.getElementById("articles").appendChild(newArticle); } }); }, false);，你需要将连接表的条件放入JOIN中。否则LEFT JOINS变成INNER JOINs

left join

MySQL离开JOIN，结果如果并非所有行都设置不起作用

1 个答案: