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Why do we always prefer using parameters in SQL statements?
I am very new to working with databases. Now I can write SELECT , UPDATE , DELETE , and INSERT commands. But I have seen many forums where we prefer to write:
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Select rows of a matrix that meet a condition
...20, ncol = 4)
colnames(m) <- letters[1:4]
The following command will select the first row of the matrix above.
subset(m, m[,4] == 16)
And this will select the last three.
subset(m, m[,4] > 17)
The result will be a matrix in both cases.
If you want to use column names to select columns...
jQuery selector regular expressions
...d or regular expressions (not sure on the exact terminology) with a jQuery selector.
10 Answers
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SQL RANK() versus ROW_NUMBER()
...he first 3 rows are tied when ordered by ID)
WITH T(StyleID, ID)
AS (SELECT 1,1 UNION ALL
SELECT 1,1 UNION ALL
SELECT 1,1 UNION ALL
SELECT 1,2)
SELECT *,
RANK() OVER(PARTITION BY StyleID ORDER BY ID) AS 'RANK',
ROW_NUMBER() OVER(PARTITION BY Style...
postgresql - replace all instances of a string within text field
...g regex replacment. Let's see how easy it is to replace a cat with a dog.
SELECT regexp_replace('Cat bobcat cat cats catfish', 'cat', 'dog');
--> Cat bobdog cat cats catfish
SELECT regexp_replace('Cat bobcat cat cats catfish', 'cat', 'dog', 'i');
--> dog...
Add a column to a table, if it does not already exist
...onstruct by using the sys.columns table io sys.objects.
IF NOT EXISTS (
SELECT *
FROM sys.columns
WHERE object_id = OBJECT_ID(N'[dbo].[Person]')
AND name = 'ColumnName'
)
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Highlight all occurrence of a selected word?
How can I highlight all occurrence of a selected word in GVim, like in Notepad++?
15 Answers
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Correct use of Multimapping in Dapper
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I just ran a test that works fine:
var sql = "select cast(1 as decimal) ProductId, 'a' ProductName, 'x' AccountOpened, cast(1 as decimal) CustomerId, 'name' CustomerName";
var item = connection.Query<ProductItem, Customer, ProductItem>(sql,
(p, c) => { p.Cu...
Android: create a popup that has multiple selection options
... Hello, can you also show how I can set actions for specific item selections? Example: I want to let the user change the app language by clicking one of those items (probably using if statement).
– Arda Çebi
Feb 7 '18 at 20:11
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How do I search within an array of hashes by hash values in ruby?
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You're looking for Enumerable#select (also called find_all):
@fathers.select {|father| father["age"] > 35 }
# => [ { "age" => 40, "father" => "Bob" },
# { "age" => 50, "father" => "Batman" } ]
Per the documentation, it "returns a...