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SQL UPDATE all values in a field with appended string CONCAT not working
...
That's pretty much all you need:
mysql> select * from t;
+------+-------+
| id | data |
+------+-------+
| 1 | max |
| 2 | linda |
| 3 | sam |
| 4 | henry |
+------+-------+
4 rows in set (0.02 sec)
mysql> update t set data=concat(d...
Laravel Schema onDelete set null
...cument what options there are, but I think you can assume it's the default mysql values (see ../ vendor / laravel / framework / src / Illuminate / Database / Schema / Grammars / Grammar.php)
– Dirk Jan
Mar 23 at 14:47
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What is the most efficient/elegant way to parse a flat table into a tree?
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Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELE...
Cannot change column used in a foreign key constraint
... DELETE ) will wait till timeout or UNLOCK TABLES; is executed
http://dev.mysql.com/doc/refman/5.5/en/lock-tables.html
EDIT 2: OP asked for a more detailed explanation of the line "The type and definition of foreign key field and reference must be equal. This means your foreign key disallows chang...
B-Tree vs Hash Table
In MySQL, an index type is a b-tree, and access an element in a b-tree is in logarithmic amortized time O(log(n)) .
5 Answ...
How do I put an 'if clause' in an SQL string?
So here's what I want to do on my MySQL database.
9 Answers
9
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How to change the CHARACTER SET (and COLLATION) throughout a database?
Our previous programmer set the wrong collation in a table (Mysql). He set it up with Latin collation, when it should be UTF8, and now I have issues. Every record with Chinese and Japan character turn to ??? character.
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NoSQL - MongoDB vs CouchDB [closed]
...ch, filling up disks.
For example: For most things that you would do with MySQL or PostgreSQL, but having predefined columns really holds you back.
CouchDB (1.2)
Written in: Erlang
Main point: DB consistency, ease of use
License: Apache
Protocol: HTTP/REST
Bi-directional (!) replication,
continu...
Why use sprintf function in PHP?
...example, forcing 2dp, 4-digit numbers, etc. It's quite useful for building MySQL query strings.
Another advantage is that it allows you to separate the layout of the string from the data being fed into it, almost like feeding in paramaters. For example, in the case of a MySQL query:
// For securit...
GROUP_CONCAT ORDER BY
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@aleroot, Is this query MySQL specific?
– Pacerier
Apr 30 '15 at 20:24
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