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MySQL: Transactions vs Locking Tables
...ransactions vs locking tables to ensure database integrity and make sure a SELECT and UPDATE remain in sync and no other connection interferes with it. I need to:
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Is there a MySQL option/feature to track history of changes to records?
...i AFTER INSERT ON MyDB.data FOR EACH ROW
INSERT INTO MyDB.data_history SELECT 'insert', NULL, NOW(), d.*
FROM MyDB.data AS d WHERE d.primary_key_column = NEW.primary_key_column;
CREATE TRIGGER MyDB.data__au AFTER UPDATE ON MyDB.data FOR EACH ROW
INSERT INTO MyDB.data_history SELECT 'up...
PHP - add item to beginning of associative array [duplicate]
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You could use the union operator:
$arr1 = array('key0' => 'value0') + $arr1;
or array_merge.
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mysql update column with value from another table
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Second possibility is,
UPDATE TableB
SET TableB.value = (
SELECT TableA.value
FROM TableA
WHERE TableA.name = TableB.name
);
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View's SELECT contains a subquery in the FROM clause
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As per documentation:
MySQL Docs
The SELECT statement cannot contain a subquery in the FROM clause.
Your workaround would be to create a view for each of your subqueries.
Then access those views from within your view view_credit_status
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SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
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MySQL case sensitive query [duplicate]
...ing for 'value'. However it will return 'VALUE', 'value', 'VaLuE', etc…
SELECT * FROM `table` WHERE `column` = 'value'
The good news is that if you need to make a case-sensitive query, it is very easy to do using the BINARY operator, which forces a byte by byte comparison:
SELECT * FROM `table...
MySQL: Large VARCHAR vs. TEXT?
... @Pacerier another interesting example is mentioned in the comments of the selected answer, basically he had a front-end limit of 2,000 characters but the characters introduced were in a codepage that in reality used more bytes than normal letters, his database ended up needing space for 24k charact...
MySQL pagination without double-querying?
...p a lot.
The other way is to use SQL_CALC_FOUND_ROWS clause and then call SELECT FOUND_ROWS(). apart from the fact you have to put the FOUND_ROWS() call afterwards, there is a problem with this: There is a bug in MySQL that this tickles that affects ORDER BY queries making it much slower on large t...
Cannot use identity column key generation with ( TABLE_PER_CLASS )
...refer using 'TABLE' id generation strategy as it triggers lots of queries (select, insert, and update) and maintains locks to generate unique values for primary key. So what would be an alternate solution to this If we have a kinda big Inheritance scenario? It will certainly impact the performance a...