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Calculate difference between two datetimes in MySQL
I am storing the last login time in MySQL in, datetime -type filed. When users logs in, I want to get the difference between the last login time and the current time (which I get using NOW() ).
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How do I get SUM function in MySQL to return '0' if no values are found?
Say I have a simple function in MySQL:
4 Answers
4
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致PHP路上的“年轻人” - 杂谈 - 清泛网 - 专注C/C++及内核技术
...落的“过来人”，还是想写点东西给“年轻人”。
关于如何成长？
我直白的答案还是建议通过实践，通过项目来成长。虽然提倡多参加项目，但项目不能是乱七八糟的项目什么都去尝试做，对于刚工作的同学，希望做这两类...
Compare dates in MySQL
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For people comming from google: date type in mysql comes in yyyy-mm-dd format.
– Błażej Michalik
Nov 29 '15 at 20:24
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How do you configure Django for simple development and deployment?
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development, but on a live server something more robust is
often needed ( MySQL / PostgreSQL , for example).
Invariably, there are other changes to make to the Django
settings as well: different logging locations / intensities,
media paths, etc.
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Simulating group_concat MySQL function in Microsoft SQL Server 2005?
I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).
11 Answers
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Where is the Java SDK folder in my computer? Ubuntu 12.04
...in /usr/bin/java.
Dig again:
Step 2:
$ ls -l /usr/bin/java
lrwxrwxrwx 1 root root 22 2009-01-15 18:34 /usr/bin/java -> /etc/alternatives/java
So, now we know that /usr/bin/java is actually a symbolic link to /etc/alternatives/java.
Dig deeper using the same method above:
Step 3:
$ ls -l /...
Convert text into number in MySQL query
Is it possible to convert text into number within MySQL query? I have a column with an identifier that consists a name and a number in the format of "name-number". The column has VARCHAR type. I want to sort the rows according the number (rows with the same name) but the column is sorted according d...
Ordering by specific field value first
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There's also the MySQL FIELD function.
If you want complete sorting for all possible values:
SELECT id, name, priority
FROM mytable
ORDER BY FIELD(name, "core", "board", "other")
If you only care that "core" is first and the other values ...
MySQL remove all whitespaces from the entire column
...UPDATE `table` SET `col_name` = REPLACE(`col_name`, '\n', '')
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_replace
To remove first and last space(s) of column :
UPDATE `table` SET `col_name` = TRIM(`col_name`)
http://dev.mysql.com/doc/refman/5.0/en/string-functions.htm...