大约有 40,000 项符合查询结果（耗时：0.0650秒） [XML]
Ruby: Can I write multi-line string with no concatenation?
... HEREDOC syntax (via this link):
p <<END_SQL.gsub(/\s+/, " ").strip
SELECT * FROM users
ORDER BY users.id DESC
END_SQL
# >> "SELECT * FROM users ORDER BY users.id DESC"
The latter would mostly be for situations that required more flexibility in the processing. I personall...
powershell - extract file name and extension
...tated, use the BaseName and Extension properties:
PS C:\> dir *.xlsx | select BaseName,Extension
BaseName Extension
-------- ---------
StackOverflow.com Test Config .xlsx
If you are given the file name as part of string...
WHERE vs HAVING
Why do you need to place columns you create yourself (for example select 1 as "number" ) after HAVING and not WHERE in MySQL?
...
Linq to Sql: Multiple left outer joins
... .Where(s => s.Id == order.StatusId)
.DefaultIfEmpty()
select new { Order = order, Vendor = vendor, Status = status }
//Vendor and Status properties will be null if the left join is null
Here is another left join example
var results =
from expense in expenseDataConte...
Nexus 7 not visible over USB via “adb devices” from Windows 7 x64
...he Nexus, or undoubtedly any other device. Not exactly obvious, but if you select the second option "Camera (PTP)" the device is available for debugging (the lesson is ignore the camera, and focus on the protocol PTP).
This configuration is persistent, and I'm guessing that with a brand new device...
How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?
I am trying to dump the contents of a table to a csv file using a MySQL SELECT INTO OUTFILE statement. If I do:
13 Answers...
MySQL/SQL: Group by date only on a Datetime column
...
Cast the datetime to a date, then GROUP BY using this syntax:
SELECT SUM(foo), DATE(mydate) FROM a_table GROUP BY DATE(a_table.mydate);
Or you can GROUP BY the alias as @orlandu63 suggested:
SELECT SUM(foo), DATE(mydate) DateOnly FROM a_table GROUP BY DateOnly;
Though I don't think...
Possible to perform cross-database queries with PostgreSQL?
... executes a query in a remote database
dblink executes a query (usually a SELECT, but it can be any SQL
statement that returns rows) in a remote database.
When two text arguments are given, the first one is first looked up as
a persistent connection's name; if found, the command is executed on
that...
What's the purpose of SQL keyword “AS”?
...ynes Yes. Just concatenate (||) the columns and then give it an alias e.g. SELECT foo || bar AS foobar.
– Rupert Madden-Abbott
Dec 10 '18 at 14:26
...
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...