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CROSS JOIN vs INNER JOIN in SQL
...ame situation.
These 2 examples will return the same result:
Cross join
select * from table1 cross join table2 where table1.id = table2.fk_id
Inner join
select * from table1 join table2 on table1.id = table2.fk_id
Use the last method
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How can I list all foreign keys referencing a given table in SQL Server?
...get around this by creating a table, store the result into the table, then select the specific columns. Check out this link for an example :).
– John Odom
Apr 28 '15 at 19:04
3
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Check if a Postgres JSON array contains a string
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As of PostgreSQL 9.4, you can use the ? operator:
select info->>'name' from rabbits where (info->'food')::jsonb ? 'carrots';
You can even index the ? query on the "food" key if you switch to the jsonb type instead:
alter table rabbits alter info type jsonb using ...
What's the Linq to SQL equivalent to TOP or LIMIT/OFFSET?
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In VB:
from m in MyTable
take 10
select m.Foo
This assumes that MyTable implements IQueryable. You may have to access that through a DataContext or some other provider.
It also assumes that Foo is a column in MyTable that gets mapped to a property name.
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IN clause and placeholders
...mes = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + makePlaceholders(names.length) + ")";
Cursor cursor = mDb.rawQuery(query, names);
Just make sure to pass exactly as many values as places. The default maximum limit of host pa...
Oracle “Partition By” Keyword
...d then use that in a calculation against this records salary without a sub select, which is much faster.
Read the linked AskTom article for further details.
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Only read selected columns
...from the data.table-package:
You can specify the desired columns with the select parameter from fread from the data.table package. You can specify the columns with a vector of column names or column numbers.
For the example dataset:
library(data.table)
dat <- fread("data.txt", select = c("Year...
How do I set the selected item in a comboBox to match my string using C#?
..." and my comboBox contains test1 , test2 , and test3 . How do I set the selected item to "test1"? That is, how do I match my string to one of the comboBox items?
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Is it possible to use JS to open an HTML select to show its option list? [duplicate]
Is it possible to use JavaScript to open an HTML select to show its option list?
11 Answers
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Rails ActiveRecord date between
...ne day. The field is part of the standard timestamps, is created_at . The selected date is coming from a date_select .
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