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How to change MySQL column definition?
I have a mySQL table called test:
3 Answers
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Unique constraint that allows empty values in MySQL
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Yes, you can do this. See the MySQL reference (version 5.5).
A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all eng...
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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What are the differences between struct and class in C++?
...ate by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, while the struct keyword cannot be so used.
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How to select the last record of a table in SQL?
...s something like
Sql Server
SELECT TOP 1 * FROM Table ORDER BY ID DESC
MySql
SELECT * FROM Table ORDER BY ID DESC LIMIT 1
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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 ...
How Scalable is SQLite? [closed]
I recently read this Question about SQLite vs MySQL and the answer pointed out that SQLite doesn't scale well and the official website sort-of confirms this , however.
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MFC中ComboBox控件的使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
MFC中ComboBox控件的使用一、如何添加 删除Combo Box内容1，在ComboBox控件属性的Data标签里面添加，一行表示ComboBox下拉列表中的一行。换行用ctrl+回车。2，在程...一、如何添加/删除Combo Box内容
1，在ComboBox控件属性的Data标签里面添...
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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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...