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Importance of varchar length in MySQL table
I have a MySQL table where rows are inserted dynamically. Because I can not be certain of the length of strings and do not want them cut off, I make them varchar(200) which is generally much bigger than I need. Is there a big performance hit in giving a varchar field much more length than necessar...
How to subtract 30 days from the current datetime in mysql?
How do I subtract 30 days from the current datetime in mysql?
8 Answers
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Is it a good idea to index datetime field in mysql?
...etime clause to select data. Is it a good idea to index datetime fields in mysql database?
2 Answers
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Dropping Unique constraint from MySQL table
How can I drop the "Unique Key Constraint" on a column of a MySQL table using phpMyAdmin?
10 Answers
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What does `unsigned` in MySQL mean and when to use it?
What does "unsigned" mean in MySQL and when should I use it?
1 Answer
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Maximum length of a table name in MySQL
What is the maximum length of a table name in MySQL?
4 Answers
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How can I add comments in MySQL?
I want to add comment in SQL code. How can I do this? I'm using MySQL.
6 Answers
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How to delete a column from a table in MySQL
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Here's a working example.
Note that the COLUMN keyword is optional, as MySQL will accept just DROP IsDeleted. Also, to drop multiple columns, you have to separate them by commas and include the DROP for each one.
ALTER TABLE tbl_Country
DROP COLUMN IsDeleted,
DROP COLUMN CountryName;
This...
Mysql substr和Oracle substr区别 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
Mysql substr和Oracle substr区别Oracle substr(字符串，开始索引、从0起，长度)Mysql substr或substring(字符串，开始索引、从1起，长度)Oracle substr(字符串，开始索引、从0起，长度)
Mysql substr或substring(字符串，开始索引、从1起，长度)Mysql Orac...
mysql实现split分割字符串（length, SUBSTRING_INDEX, substring） - 数据...
mysql实现split分割字符串（length, SUBSTRING_INDEX, substring）由于MySql没有直接的split函数，只提供了length, SUBSTRING_INDEX, substring三个函数，这里介绍如何用这三个函数实现split功能。# SUBS...由于MySql没有直接的split函数，只提供了length, SUB...