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Join between tables in two different databases?
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Yes, assuming the account has appropriate permissions you can use:
SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;
You just need to prefix the table reference with the name of the database it resides in.
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What is a proper naming convention for MySQL FKs?
... foreign key constraint name by running a query:
use information_schema;
select TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME from KEY_COLUMN_USAGE where REFERENCED_TABLE_SCHEMA = 'your_db_schema_name' ORDER BY TABLE_NAME;
For example you might receive the ...
How to change the foreign key referential action? (behavior)
...r, so I wrote something to make the statements for me. Figured I'd share:
SELECT
CONCAT('ALTER TABLE `' ,rc.TABLE_NAME,
'` DROP FOREIGN KEY `' ,rc.CONSTRAINT_NAME,'`;')
, CONCAT('ALTER TABLE `' ,rc.TABLE_NAME,
'` ADD CONSTRAINT `' ,rc.CONSTRAINT_NAME ,'` FOREIGN KEY (`',kcu.COLUMN_NAME,
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How can I add reflection to a C++ application?
...ble with C++.
Inspection by checking whether a class-type (class, struct, union) has a method or nested type, is derived from another particular type.
This kind of thing is possible with C++ using template-tricks. Use boost::type_traits for many things (like checking whether a type is integral). Fo...
How to read multiple text files into a single RDD?
...Dirs,320) it leads to 19430 total tasks instead of 320 ... it behaves like union which also leads to insane number of tasks from very low parallelism
– lisak
Nov 25 '15 at 10:51
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jQuery OR Selector?
I am wondering if there is a way to have "OR" logic in jQuery selectors. For example, I know an element is either a descendant of an element with class classA or classB, and I want to do something like elem.parents('.classA or .classB') . Does jQuery provide such functionality?
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ORDER BY the IN value list
... (introduced in PostgreSQL 8.2) VALUES (), ().
Syntax will be like this:
select c.*
from comments c
join (
values
(1,1),
(3,2),
(2,3),
(4,4)
) as x (id, ordering) on c.id = x.id
order by x.ordering
share...
How to use index in select statement?
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If you want to test the index to see if it works, here is the syntax:
SELECT *
FROM Table WITH(INDEX(Index_Name))
The WITH statement will force the index to be used.
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Increment a database field by 1
...complex depending on your specific needs:
INSERT into mytable (logins)
SELECT max(logins) + 1
FROM mytable
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MySQL - UPDATE multiple rows with different values in one query
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UPDATE Table1 SET col1= col2 FROM (SELECT col2, col3 FROM Table2) as newTbl WHERE col4= col3
Here col4 & col1 are in Table1. col2 & col3 are in Table2 I Am trying to update each col1 where col4 = col3 different value for each row
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