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Case in Select Statement
I have an SQL statement that has a CASE from SELECT and I just can't get it right. Can you guys show me an example of CASE where the cases are the conditions and the results are from the cases. For example:
...
How do I cast a string to integer and have 0 in case of error in the cast with PostgreSQL?
...dn't want the overhead of a function. I came up with the following query:
SELECT myfield::integer FROM mytable WHERE myfield ~ E'^\\d+$';
Postgres shortcuts its conditionals, so you shouldn't get any non-integers hitting your ::integer cast. It also handles NULL values (they won't match the regex...
How do I UPDATE from a SELECT in SQL Server?
... SQL Server , it is possible to insert rows into a table with an INSERT.. SELECT statement:
35 Answers
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Why is it OK to return a 'vector' from a function?
...oing to return a..." << std::endl;
return a;
}
int main(int argc, char** argv)
{
MyClass b = my_function();
MyClass c;
c = my_function();
return 0;
}
The output is the following:
run my_function()
run constructor MyClass::MyClass()
my_function is going to return a...
run constr...
Split function equivalent in T-SQL?
...AR(2048) = 'Mike/John/Miko/Matt'; DECLARE CaracString NVARCHAR(1) = '/'; SELECT * FROM dbo.FnSplitString (VarString, CaracString)
– fernando yevenes
Feb 8 '19 at 15:57
ad...
What is your favorite C programming trick? [closed]
.... you could make a string "object" like this:
struct X {
int len;
char str[1];
};
int n = strlen("hello world");
struct X *string = malloc(sizeof(struct X) + n);
strcpy(string->str, "hello world");
string->len = n;
here, we've allocated a structure of type X on the heap that is the...
How to select all instances of selected region in Sublime Text
Is there a shortcut key or single-step menu option to find and select all instances of a highlighted selection in Sublime Text?
...
How do I get the current time zone of MySQL?
...bal and client-specific time zones can be retrieved like this:
mysql> SELECT @@global.time_zone, @@session.time_zone;
Edit The above returns SYSTEM if MySQL is set to slave to the system's timezone, which is less than helpful. Since you're using PHP, if the answer from MySQL is SYSTEM, you ca...
How can prepared statements protect from SQL injection attacks?
...ample shows it (all examples in PHP/Mysql):
$expected_data = 1;
$query = "SELECT * FROM users where id=$expected_data";
will produce a regular query
SELECT * FROM users where id=1
while this code
$spoiled_data = "1; DROP TABLE users;"
$query = "SELECT * FROM users where id=$spoiled_da...
Find most frequent value in SQL column
...
SELECT `column`,
COUNT(`column`) AS `value_occurrence`
FROM `my_table`
GROUP BY `column`
ORDER BY `value_occurrence` DESC
LIMIT 1;
Replace column and my_table. Increase 1 if you wa...