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How to do a FULL OUTER JOIN in MySQL?
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For a code SAMPLE transcribed from this SO question you have:
with two tables t1, t2:
SELECT * FROM t1
LEFT JOIN t2 ON t1.id = t2.id
UNION
SELECT * FROM t1
RIGHT JOIN t2 ON t1.id = t2.id
The query above works for special cases where a FULL OUTER JOIN operation would not produce any duplicat...
How to get last inserted row ID from WordPress database?
My WordPress plugin has a table with a AUTO_INCREMENT primary key field called ID. When a new row is inserted into the table, I'd like to get the ID value of the insertion.
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Is there a MySQL command to convert a string to lowercase?
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UPDATE table SET colname=LOWER(colname);
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Explaining difference between automaticallyAdjustsScrollViewInsets, extendedLayoutIncludesOpaqueBars
...his property is used when your view is a UIScrollView or similar, like a UITableView. You want your table to start where the navigation bar ends, because you wont see the whole content if not, but at the same time you want your table to cover the whole screen when scrolling. In that case, setting ed...
data.frame rows to a list
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@AaronMcDaid Or data.table::rbindlist(). If your original data frame was large, the speed gains will be significant.
– Empiromancer
Jul 12 '16 at 22:04
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Why does PostgreSQL perform sequential scan on indexed column?
Very simple example - one table, one index, one query:
4 Answers
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What is the difference between user and kernel modes in operating systems?
... the application with a private virtual address space and a private handle table. Because an application's virtual address space is private, one application cannot alter data that belongs to another application. Each application runs in isolation, and if an application crashes, the crash is limited ...
What is sharding and why is it important?
... Horizontal partitioning is a design principle whereby rows of a database table are held separately, rather than splitting by columns (as for normalization). Each partition forms part of a shard, which may in turn be located on a separate database server or physical location. The advantage is the n...
SQL Server - copy stored procedures from one db to another
...into one. I did that using SQL Server 2008 Manager - Tasks > Import/Export tables.The tables and views were copied successfully, but there are no Stored procedures in the new database. Is there any way to do that?
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Use email address as primary key?
...ies with multiple joins.
If you store information about users in multiple tables, the foreign keys to the users table will be the e-mail address. That means that you store the e-mail address multiple times.
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