大约有 47,000 项符合查询结果（耗时：0.0420秒） [XML]
SELECT * WHERE NOT EXISTS
...uming these tables should be joined on employeeID, use the following:
SELECT *
FROM employees e
WHERE NOT EXISTS
(
SELECT null
FROM eotm_dyn d
WHERE d.employeeID = e.id
)
You can join these tables with a LEFT JOIN keyword and filter out the...
Join vs. sub-query
...
@JinghuiNiu Customers who bought expensive items: select custid from cust join bought using (custid) where price > 500. If a customer bought multiple expensive items, you'll get double-ups. To fix this, select custid from cust where exists (select * from bought where cust...
How can I remove the gloss on a select element in Safari on Mac?
On Macs and iOS devices, in Safari, a <select> element with a background color generates a gloss over itself. This does not seem to happen in other operating systems.
...
Rename package in Android Studio
...n:
In your Project pane, click on the little gear icon ( )
Uncheck / De-select the Compact Empty Middle Packages option
Your package directory will now be broken up in individual directories
Individually select each directory you want to rename, and:
Right-click it
Select Refactor
Click o...
How to “add existing frameworks” in Xcode 4?
...
As per Apple's documentation:
In the project navigator, select
your project.
Select your target.
Select the "Build Phases" tab.
Open "Link Binaries With Libraries"
expander.
Click the + button.
Select your framework.
(optional) Drag and drop the added
framework to the "Framework...
How to do this in Laravel, subquery where in
...sider this code:
Products::whereIn('id', function($query){
$query->select('paper_type_id')
->from(with(new ProductCategory)->getTable())
->whereIn('category_id', ['223', '15'])
->where('active', 1);
})->get();
...
Adding 'serial' to existing column in Postgres
...int, b text);
CREATE TABLE bar (a serial, b text);
INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;
-- blocks of commands to turn foo into bar
CREATE SEQUENCE foo_a_seq;
ALTER TABLE foo ALTER...
SQL injection that gets around mysql_real_escape_string()
...ollowing query:
$iId = mysql_real_escape_string("1 OR 1=1");
$sSql = "SELECT * FROM table WHERE id = $iId";
mysql_real_escape_string() will not protect you against this.
The fact that you use single quotes (' ') around your variables inside your query is what protects you against this. The fo...
How to check if a table exists in a given schema
... whether a table (or view) exists, and the current user has access to it?
SELECT EXISTS (
SELECT FROM information_schema.tables
WHERE table_schema = 'schema_name'
AND table_name = 'table_name'
);
The information schema is mainly useful to stay portable across major versions and...
FIND_IN_SET() vs IN()
...
SELECT name
FROM orders,company
WHERE orderID = 1
AND companyID IN (attachedCompanyIDs)
attachedCompanyIDs is a scalar value which is cast into INT (type of companyID).
The cast only returns numbers up to the...