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Difference Between Schema / Database in MySQL
...racle Database product, a schema represents only a part of a database: the tables and other objects owned by a single user.
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MySQL offset infinite rows
I would like to construct a query that displays all the results in a table, but is offset by 5 from the start of the table. As far as I can tell, MySQL's LIMIT requires a limit as well as an offset. Is there any way to do this?
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How to create composite primary key in SQL Server 2008
I want to create tables in SQL Server 2008, but I don't know how to create composite primary key. How can I achieve this?
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how can I Update top 100 records in sql server
I want to update the top 100 records in SQL Server. I have a table T1 with fields F1 and F2 . T1 has 200 records. I want to update the F1 field in the top 100 records. How can I update based on TOP 100 in SQL Server?
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Relative frequencies / proportions with dplyr
...our depending on the version of dplyr:
dplyr 0.7.1: returns an ungrouped table: you need to group again by am
dplyr < 0.7.1: returns a grouped table, so no need to group again, although you might want to ungroup() for later manipulations
dplyr 0.7.1
mtcars %>%
count(am, gear) %>%
g...
generate days from date range
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This solution uses no loops, procedures, or temp tables. The subquery generates dates for the last 10,000 days, and could be extended to go as far back or forward as you wish.
select a.Date
from (
select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a) + (1000 * d...
LINQ to SQL Left Outer Join
..."left" row in a left-outer-join will match 0-n "right" rows (in the second table), where-as yours matches only 0-1. To do a left outer join, you need SelectMany and DefaultIfEmpty, for example:
var query = from c in db.Customers
join o in db.Orders
on c.CustomerID equals o...
B-Tree vs Hash Table
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You can only access elements by their primary key in a hashtable.
This is faster than with a tree algorithm (O(1) instead of log(n)), but you cannot select ranges (everything in between x and y).
Tree algorithms support this in Log(n) whereas hash indexes can result in a full table s...
clear table jquery
I have an HTML table filled with a number of rows.
10 Answers
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SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?
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Cascade will work when you delete something on table Courses. Any record on table BookCourses that has reference to table Courses will be deleted automatically.
But when you try to delete on table BookCourses only the table itself is affected and not on the Courses
foll...