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SQL用了Union后的排序问题

有小伙伴反映：

最近使用SQL语句进行UNION查询，惊奇的发现：SQL没问题，UNION查询也没问题，都可以得到想要的结果，可是在对结果进行排序的时候，却出问题了。

 

SELECT a.id,a.username,a.mobile,a.time,a.leader,a.time
FROM (SELECT `id`,`username`,`mobile`,`time`,id AS leader 
	FROM `grouporder_leader` WHERE `courseid` = 21 AND `merchid` = 23 AND `status` = 1 
	UNION ALL 
	SELECT leadorderid,username,mobile,time,null 
	FROM `grouporder_partner` WHERE courseid=21 and status=1 and merchid=23
) AS a 
ORDER BY a.time DESC

注意事项：

1、必须声明临时表；

2、必须使用别名

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js关闭浏览器的tab页(兼容)

由于在脚本中使用了 window.close(), 当前非弹出窗口在最新版本的chrome和firefox里总是不能关闭，而在 IE中是可以关闭的 。

      在console中弹出提示”Scripts may close only the windows that were opened by it” (脚本只能关闭它所打开的窗口),[如下图所示] , 不明白是什么原因。

首先，什么是非弹出窗口呢？

      非弹出窗口，即是指（opener=null 及 非window.open()打开的窗口,比如URL直接输入的浏览器窗体， 或由其它程序调用产生的浏览器窗口）。

其次，window.close() 怎么理解呢？

 

由 https://developer.mozilla.org/en-US/docs/Web/API/window.close 可知:

Closes the current window, or the window on which it was called.
When this method is called, the referenced window is closed.

This method is only allowed to be called for windows that were opened by a script using thewindow.open() method. If the window was not opened by a script, the following error appears in the JavaScript Console: Scripts may not close windows that were not opened by script.

Examples

Closing a window opened with window.open()

This example demonstrates how to use this method to close a window opened by script callingwindow.open().

<script type="text/javascript">
//Global var to store a reference to the opened window
var openedWindow;

function openWindow()
{
  openedWindow = window.open('moreinfo.htm');
}

function closeOpenedWindow()
{
  openedWindow.close();
}
</script>

Closing the current window

When you call the window object’s close() method directly, rather than calling close() on a windowinstance, the browser will close the frontmost window, whether your script created that window or not.

<script type="text/javascript">
function closeCurrentWindow()
{
  window.close();
}
</script>

在某些实际应用中，window.close() and self.close() 是不能关闭非弹出窗口（opener=null及非window.open()打开的窗口）。

方案一【推荐，亲身测试有效！！】：

function closeWindows() {
         var browserName = navigator.appName;
         var browserVer = parseInt(navigator.appVersion);
         //alert(browserName + " : "+browserVer);

         //document.getElementById("flashContent").innerHTML = "<br>&nbsp;<font face='Arial' color='blue' size='2'><b> You have been logged out of the Game. Please Close Your Browser Window.</b></font>";

         if(browserName == "Microsoft Internet Explorer"){
             var ie7 = (document.all && !window.opera && window.XMLHttpRequest) ? true : false;  
             if (ie7)
             {  
               //This method is required to close a window without any prompt for IE7 & greater versions.
               window.open('','_parent','');
               window.close();
             }
            else
             {
               //This method is required to close a window without any prompt for IE6
               this.focus();
               self.opener = this;
               self.close();
             }
        }else{  
            //For NON-IE Browsers except Firefox which doesnt support Auto Close
            try{
                this.focus();
                self.opener = this;
                self.close();
            }
            catch(e){

            }

            try{
                window.open('','_self','');
                window.close();
            }
            catch(e){

            }
        }
    }

方案二：

<script type="text/javascript">
function closeWP() {
 var Browser = navigator.appName;
 var indexB = Browser.indexOf('Explorer');

 if (indexB > 0) {
    var indexV = navigator.userAgent.indexOf('MSIE') + 5;
    var Version = navigator.userAgent.substring(indexV, indexV + 1);

    if (Version >= 7) {
        window.open('', '_self', '');
        window.close();
    }
    else if (Version == 6) {
        window.opener = null;
        window.close();
    }
    else {
        window.opener = '';
        window.close();
    }

 }
else {
    window.close();
 }
}
</script>

参考：https://www.cnblogs.com/exe19/p/5546719.html