我在MySQL数据库中有两个表:
照片:
PID - PhotoID [PK],
DateOf - DateTime of uploading,
UID -UserID (owner of the photo)
评级:
WhoUID - UserID who rated,
DateOf - DateTime of rate,
RatingValue - +1 or -1 (positive or negative),
RatingStrength - coefficient (different for each user who vote)
PID - PhotoID, [FK]
我有以下疑问: SELECT floor(datediff(u.created_at, curdate()) / 1) AS days_ago,
count(DISTINCT u.id) AS "New Users in Cohort",
count(DISTINCT i.user_id) AS "Uniq Users who invited Cohort",
count(DISTINCT u.id) / count(DISTINCT i.user_id) AS "% who invite"
FROM users
当我试图在我的程序中使用jxcore.tasks.addTask函数时,我得到了这个错误。
undefined:1
function (){}
^
SyntaxError: Unexpected token u
at Object.parse (native)
at gcc (_jx_tasks.js:130:24)
at process.<anonymous> (_jx_tasks.js:425:3)
at process.emit (events.js:106:17)
at process.__makeCall (node.js:420
我发现很难从MongoDB驱动程序中找到一种方法来查看数据库是否存在于Node.js中。Node.js驱动程序中似乎没有检查数据库是否存在的方法。
例如,以下内容不会引发错误:
var mongo = require('mongodb').MongoClient;
mongo.connect({ 'mongodb://localhost:27017/databaseThatDoesntExists }, function (err, db) {
// There is no error
if (err) console.log(err);
// Le
我遵循以下步骤:
在命令行中运行swank-js。
运行emacs。
M黏液连接。
主机: 127.0.0.1;端口: 4005
打开火狐中的http://localhost:8009/swank-js/test.html。
接收:“远程附加:(浏览器) Firefox14.0”在emacs REPL中。
在REPL中运行"document“命令。
此时,我收到错误:
ReferenceError: document is not defined
at repl:1:1
at DefaultRemote.evaluate (/usr/
如果我想每天运行一个报告,并将报告的日期存储为列标题之一。这个是可能的吗?
输出示例(统计员工当天的活动):
SELECT EMPLOYEE_NAME AS EMPLOYEE, COUNT(ACTIVITY) AS "Activity_On_SYSDATE" FROM EMPLOYEE_ACCESS GROUP BY EMPLOYEE_NAME;
Employee Activity_On_17042016
Jane 5
Martha 8
Sam 11