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GROUP_CONCAT ORDER BY
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You can use ORDER BY inside the GROUP_CONCAT function in this way:
SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views,
group_concat(li.percentage ORDER BY li.percentage ASC)
FROM li GROUP BY client_id
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MySQL Removing Some Foreign keys
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You can use this to find foreign key constraints: SELECT * FROM information_schema.table_constraints WHERE constraint_schema = '<your db name>' AND constraint_type = 'FOREIGN KEY'
– Gayan Dasanayake
Aug 26 '17 at 2:48
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App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎 ...
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SQLite 拓展
SQLite
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如何使用
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常规
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绑定参数
案例
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MySQL: Sort GROUP_CONCAT values
... see http://dev.mysql.com/doc/refman/...tions.html#function_group-concat:
SELECT student_name,
GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
FROM student
GROUP BY student_name;
share
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What is the difference between BIT and TINYINT in MySQL?
...deployed everything on linux, I had problems with queries that inserted or selected from tables that had BIT DATA TYPE.
Bit is not safe for now.
I changed to tinyint(1) and worked perfectly. I mean that you only need a value to diferentiate if it's 1 or 0 and tinyint(1) it's ok for that
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How to select all records from one table that do not exist in another table?
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SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 wi...
Does MySQL ignore null values on unique constraints?
... '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This is not true for all databases. SQL Server 2005 and older, for example, only allows a single NULL value in a column that has a unique constraint.
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实战Nginx与PHP（FastCGI）的安装、配置与优化 - 更多技术 - 清泛网 - 专注...
...进行了详细介绍，这里不再进行讲述。下面重点介绍Nginx如何通过php-fpm的FastCGI进程对PHP进行解析处理。
由于Ｎginx本身不会对PHP进行解析，因此要实现Nginx对PHP的支持，其实是将对PHP页面的请求交给fastCGI进程监听的IP地址及端口...
Should I commit or rollback a read transaction?
... I create a temp table, populate it with ids, join it with a data table to select the data that goes with the ids, then delete the temp table. I'm really just reading data, and I don't care what happens to the temp table, since it's temporary... but from a performance perspective, would it be more ...
Add list to set?
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With respect to sets, the | operator implements the set union operation. Both the |= operator and set.update() method apply that operation in-place and are effectively synonymous. So, set_a |= set_b could be considered syntactic sugar for both set_a.update(set_b) and set_a = set_a...