大约有 42,000 项符合查询结果（耗时：0.0421秒） [XML]
Set value to NULL in MySQL
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You're probably quoting 'NULL'. NULL is a reserved word in MySQL, and can be inserted/updated without quotes:
INSERT INTO user (name, something_optional) VALUES ("Joe", NULL);
UPDATE user SET something_optional = NULL;
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How to find Unused Amazon EC2 Security groups
... from complete. So I decided to write my own script. I used the AWS CLI, MySQL and some “Bash-foo” to perform the following:
Get a list of all EC2 security groups.
I store the group-id, group-name and description in a tabled called “groups” in a MySQL database called aws_security_groups ...
Get Insert Statement for existing row in MySQL
Using MySQL I can run the query:
15 Answers
15
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Which ORM should I use for Node.js and MySQL? [closed]
I'm rewriting a project to use Node.js. I'd like to keep using MySQL as the DB (even though I don't mind rewriting the schema).
I'm looking for a simple-to-use, reasonable-performance ORM, which supports caching, many-to-one and many-to-many relations.
From the MySQL ORMs I could find, persistencej...
How to select date from datetime column?
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You can use MySQL's DATE() function:
WHERE DATE(datetime) = '2009-10-20'
You could also try this:
WHERE datetime LIKE '2009-10-20%'
See this answer for info on the performance implications of using LIKE.
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Best way to test if a row exists in a MySQL table
I'm trying to find out if a row exists in a table. Using MySQL, is it better to do a query like this:
12 Answers
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MySQL select 10 random rows from 600K rows fast
...imple, to gaps, to non-uniform with gaps.
http://jan.kneschke.de/projects/mysql/order-by-rand/
For most general case, here is how you do it:
SELECT name
FROM random AS r1 JOIN
(SELECT CEIL(RAND() *
(SELECT MAX(id)
FROM random)) AS id)
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家政O2O百家争鸣后的卡位战：烧钱补贴并非良药 - 资讯 - 清泛网 - 专注IT技能提升
...免去烧钱补贴做推广。但这绝对不是一个良性的生意。”如何在同质化和与巨头的竞争中突围，真正实现赢利，是所有创业者们都迫切所希望的。
用户体验是关键
无论哪种行业，若想赢得市场，用户体验都是关键。北京晨报...
家政O2O百家争鸣后的卡位战：烧钱补贴并非良药 - 资讯 - 清泛网 - 专注IT技能提升
...免去烧钱补贴做推广。但这绝对不是一个良性的生意。”如何在同质化和与巨头的竞争中突围，真正实现赢利，是所有创业者们都迫切所希望的。
用户体验是关键
无论哪种行业，若想赢得市场，用户体验都是关键。北京晨报...
家政O2O百家争鸣后的卡位战：烧钱补贴并非良药 - 资讯 - 清泛网 - 专注IT技能提升
...免去烧钱补贴做推广。但这绝对不是一个良性的生意。”如何在同质化和与巨头的竞争中突围，真正实现赢利，是所有创业者们都迫切所希望的。
用户体验是关键
无论哪种行业，若想赢得市场，用户体验都是关键。北京晨报...