大约有 45,000 项符合查询结果（耗时：0.0286秒） [XML]
Want to find records with no associated records in Rails
... get everyone with no friends in the first case:
Person.where('id NOT IN (SELECT DISTINCT(person_id) FROM friends)')
share
|
improve this answer
|
follow
|
...
How to convert string to Title Case in Python?
...his one would always start with lowercase, and also strip non alphanumeric characters:
def camelCase(st):
output = ''.join(x for x in st.title() if x.isalnum())
return output[0].lower() + output[1:]
share
...
How to check if field is null or empty in MySQL?
...
Either use
SELECT IF(field1 IS NULL or field1 = '', 'empty', field1) as field1
from tablename
or
SELECT case when field1 IS NULL or field1 = ''
then 'empty'
else field1
end as field1
from tablename
...
How can I insert values into a table, using a subquery with more than one result?
...
You want:
insert into prices (group, id, price)
select
7, articleId, 1.50
from article where name like 'ABC%';
where you just hardcode the constant fields.
share
|
...
How to check if a column exists in a SQL Server table?
...
SQL Server 2005 onwards:
IF EXISTS(SELECT 1 FROM sys.columns
WHERE Name = N'columnName'
AND Object_ID = Object_ID(N'schemaName.tableName'))
BEGIN
-- Column Exists
END
Martin Smith's version is shorter:
IF COL_LENGTH('schemaName.tabl...
SQL JOIN - WHERE clause vs. ON clause
...
They are not the same thing.
Consider these queries:
SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
WHERE Orders.ID = 12345
and
SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
AND Orders.ID = 12345
The first will re...
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
...t the solution specifically for the "opencases" column be simpler as just "select count(1)..." (or "count" of any other literal)? The Where clause already specifies "and closed is NULL" so no need for summing a case statement in this instance. Also, I've heard (aeons ago) that "count(*)" is not as e...
What's the u prefix in a Python string?
...very Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) essay on character sets.
Q: sry no time code pls
A: Fine. try str('Some String') or 'Some String'.encode('ascii', 'ignore'). But you should really read some of the answers and discussion on Conv...
PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
Adding devices to team provisioning profile
...e.com
Add the UDID in devices
Go back to XCode, open up the Organizer and select "Provisioning Profiles", ensure that "Automatic Device Provisioning" is checked on the top right pane, then click on the "Refresh" button, and magically all your devices set in the provisioning portal will be automati...