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MySQL Update Inner Join tables query
I have no idea what the problem is. Using MySQL 5.0 I get a compile error when attempting to run the following MySQL update query:
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MySQL: @variable vs. variable. What's the difference?
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MySQL has a concept of user-defined variables.
They are loosely typed variables that may be initialized somewhere in a session and keep their value until the session ends.
They are prepended with an @ sign, like this: @var
Yo...
How to Get True Size of MySQL Database?
I would like to know how much space does my MySQL database use, in order to select a web host.
I found the command SHOW TABLE STATUS LIKE 'table_name' so when I do the query, I get something like this:
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MySQL load NULL values from CSV data
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MySQL manual says:
When reading data with LOAD DATA
INFILE, empty or missing columns are
updated with ''. If you want a NULL
value in a column, you should use \N
in the data file. The literal word
“NULL” ma...
App Inventor 2 接入百度网盘API · App Inventor 2 中文网
...框】
接入文档
使用Web浏览框，里面要输入网盘用户名密码，成功后返回的url中拿出access_token
这里使用简单模式，回调网页，在回调后的URL中拿出access_token，后面操作都需要它：
http://openapi.baidu.com/oauth/2.0/authorize?display=mobil...
Error 1046 No database Selected, how to resolve?
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You need to tell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
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What's the difference between utf8_general_ci and utf8_unicode_ci?
...ncoding. The differences are in how text is sorted and compared.
Note: In MySQL you have to use utf8mb4 rather than utf8. Confusingly, utf8 is a flawed UTF-8 implementation from early MySQL versions which remains only for backward compatibility. The fixed version was given the name utf8mb4.
Note: N...
Using column alias in WHERE clause of MySQL query produces an error
...is
executed, the column value may not yet
be determined.
Copied from MySQL documentation
As pointed in the comments, using HAVING instead may do the work. Make sure to give a read at this WHERE vs HAVING though.
share...
What MySQL data type should be used for Latitude/Longitude with 8 decimal places?
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DECIMAL is the MySQL data-type for exact arithmetic. Unlike FLOAT its precision is fixed for any size of number, so by using it instead of FLOAT you might avoid precision errors when doing some calculations. If you were just storing and ret...
How to get the sizes of the tables of a MySQL database?
I can run this query to get the sizes of all tables in a MySQL database:
16 Answers
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