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Copy values from one column to another in the same table
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Short answer for the code in question is:
UPDATE `table` SET test=number
Here table is the table name and it's surrounded by grave accent (aka back-ticks `) as this is MySQL convention to escape keywords (and TABLE is a keyword in that case).
BEWARE, that this is pretty d...
Fast way to discover the row count of a table in PostgreSQL
I need to know the number of rows in a table to calculate a percentage. If the total count is greater than some predefined constant, I will use the constant value. Otherwise, I will use the actual number of rows.
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Inner join vs Where
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No! The same execution plan, look at these two tables:
CREATE TABLE table1 (
id INT,
name VARCHAR(20)
);
CREATE TABLE table2 (
id INT,
name VARCHAR(20)
);
The execution plan for the query using the inner join:
-- with inner join
EXPLAIN PLAN FOR
SELECT * FRO...
What is the difference between a stored procedure and a view?
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A view represents a virtual table. You can join multiple tables in a view and use the view to present the data as if the data were coming from a single table.
A stored procedure uses parameters to do a function... whether it is updating and inserting ...
Select multiple columns in data.table by their numeric indices
...ltiple columns using a vector of their numeric indices (position) in data.table ?
5 Answers
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MFC AfxMessageBox改变标题的几种方法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...工程名的基础上改变标题呢？其实这个标题在资源String Table里就能找到，查找AFX_IDS_APP_TITLE，在这里你就能轻而易举的改变标题了。
注意：如果工程的资源String Table里面没有添加AFX_IDS_APP_TITLE，需要手动添加。
2、修改m_pszA...
MySQL table is marked as crashed and last (automatic?) repair failed
I was repairing this table suddenly server hanged and when I returned back all tables are ok but this one showing 'in use' and when I try to repair it doesn't proceed.
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What are the uses for Cross Join?
...t
size,
color
from
sizes CROSS JOIN colors
Maybe you want a table that contains a row for every minute in the day, and you want to use it to verify that a procedure has executed each minute, so you might cross three tables:
select
hour,
minute
from
hours CROSS JOIN minute...
What's the UIScrollView contentInset property for?
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It's used to add padding in UIScrollView
Without contentInset, a table view is like this:
Then set contentInset:
tableView.contentInset = UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)
The effect is as below:
Seems to be better, right?
And I write a blog to study the content...
SQL Server equivalent to MySQL enum data type?
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Why not use a table that defines valid values, and then use a foreign key constraint instead?
– Elaskanator
Dec 5 '18 at 17:04
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