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How to best display in Terminal a MySQL SELECT returning too many fields?
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Terminate the query with \G in place of ;. For example:
SELECT * FROM sometable\G
This query displays the rows vertically, like this:
*************************** 1. row ***************************
Host: localhost
Db: mydatabase1
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Error 1046 No database Selected, how to resolve?
...ation.
If you're trying to do this via MySQL Workbench...
...you need to select the appropriate database/catalog in the drop down menu found above the :Object Browser: tab. You can specify the default schema/database/catalog for the connection - click the "Manage Connections" options under the SQL...
How can I find non-ASCII characters in MySQL?
...ng as "ASCII", but I would suggest trying a variant of a query like this:
SELECT * FROM tableName WHERE columnToCheck NOT REGEXP '[A-Za-z0-9]';
That query will return all rows where columnToCheck contains any non-alphanumeric characters. If you have other characters that are acceptable, add them ...
MySQL - UPDATE query based on SELECT Query
...can go here
ANSI SQL syntax:
UPDATE tableA SET validation_check =
(SELECT if(start_DTS > end_DTS, 'VALID', '') AS validation_check
FROM tableA
INNER JOIN tableB ON name_A = name_B
WHERE id_A = tableA.id_A)
Pick whichever one seems most natural to you.
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add column to mysql table if it does not exist
...rade_database_1_0_to_2_0()
BEGIN
-- rename a table safely
IF NOT EXISTS( (SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE()
AND TABLE_NAME='my_old_table_name') ) THEN
RENAME TABLE
my_old_table_name TO my_new_table_name,
END IF;
-- add a column safely
IF NO...
Do htmlspecialchars and mysql_real_escape_string keep my PHP code safe from injection?
...nerable to certain attack vectors.
Imagine the following SQL:
$result = "SELECT fields FROM table WHERE id = ".mysql_real_escape_string($_POST['id']);
You should be able to see that this is vulnerable to exploit.
Imagine the id parameter contained the common attack vector:
1 OR 1=1
There's no...
How to define “type disjunction” (union types)?
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Miles Sabin describes a very nice way to get union type in his recent blog post Unboxed union types in Scala via the Curry-Howard isomorphism:
He first defines negation of types as
type ¬[A] = A => Nothing
using De Morgan's law this allows him to define union ty...
优惠券批量生成及导入的思路 - 闲聊区 - 清泛IT论坛，有思想、有深度
...个事实。假设我们可以随机生成不重复的整数，那么又该如何转换成上述”字母+数字”的混合字符串形势呢？答案是：36进制。36进制数的表达区间是0-9，A-Z(a-z)，恰好满足要求。因此，我的方法是用随机函数生成长整形并转换...
MySQL maximum memory usage
...e to know how it is possible to set an upper limit on the amount of memory MySQL uses on a Linux server.
6 Answers
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How to subtract 30 days from the current datetime in mysql?
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SELECT * FROM table
WHERE exec_datetime BETWEEN DATE_SUB(NOW(), INTERVAL 30 DAY) AND NOW();
http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_date-add
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