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How do you use the “WITH” clause in MySQL?
I am converting all my SQL Server queries to MySQL and my queries that have WITH in them are all failing. Here's an example:
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MySQL ON DUPLICATE KEY UPDATE for multiple rows insert in single query
I have a SQL query where I want to insert multiple rows in single query. so I used something like:
3 Answers
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What is a None value?
...as called with an argument or not.
Other languages have similar concepts. SQL has NULL; JavaScript has undefined and null, etc.
Note that in Python, variables exist by virtue of being used. You don't need to declare a variable first, so there are no really empty variables in Python. Setting a vari...
计算统计特征（正态分布）函数及实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
...count;
if (info._count > 1) {
/* NOTE: 删除时， 最大最小值无法还原 */
/*
if (v > info._max_v)
info._max_v = v;
if (v < info._min_v)
info._min_v = v;
*/
} else {
info._max_v = info._min_v = v;
}
if (info._count > 0)
info._ave = inf...
为什么你越努力，却越焦虑？ - 杂谈 - 清泛网 - 专注C/C++及内核技术
...自控能力的缘故，也可能和性格和其他因素有关。但无论如何，我深知，只要我给自己找了借口，我就会不遗余力地开始前功尽弃。对于经常把自我宽容混同为自我纵容的人来说，任何自我怜悯的借口实际上都只是自我欺骗。
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Why should I use document based database instead of relational database?
... aren't simply accessed via REST services, but require a much more complex SQL API. Often these API's (JDBC, ODBC, etc.) are quite complex. REST is quite simple.
Ad-hoc and schema-free with a flat address space. Relational databases have complex, fixed schema. You define tables, columns, indexes...
Repair all tables in one go
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from command line you can use:
mysqlcheck -A --auto-repair
http://dev.mysql.com/doc/refman/5.0/en/mysqlcheck.html
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MYSQL Dump only certain rows
I am trying to do a mysql dump of a few rows in my database. I can then use the dump to upload those few rows into another database. The code I have is working, but it dumps everything. How can I get mysqldump to only dump certain rows of a table?
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must appear in the GROUP BY clause or be used in an aggregate function
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Yes, this is a common aggregation problem. Before SQL3 (1999), the selected fields must appear in the GROUP BY clause[*].
To workaround this issue, you must calculate the aggregate in a sub-query and then join it with itself to get the additional columns you'd need to show...
How to search a specific value in all tables (PostgreSQL)?
...e to search every column of every table for a particular value in PostgreSQL?
8 Answers
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