大约有 5,880 项符合查询结果（耗时：0.0365秒） [XML]
Why is SELECT * considered harmful?
...work. This is especially true when someone adds new columns to underlying tables that didn't exist and weren't needed when the original consumers coded their data access.
Indexing issues. Consider a scenario where you want to tune a query to a high level of performance. If you were to use *, and ...
How can I select from list of values in SQL Server
...g them:
[MS official] https://docs.microsoft.com/en-us/sql/t-sql/queries/table-value-constructor-transact-sql
http://www.sql-server-helper.com/sql-server-2008/row-value-constructor-as-derived-table.aspx
share
|
...
How to write a foreach in SQL Server?
...rforms better than a cursor and is simpler:
DECLARE @PractitionerList TABLE(PracticionerID INT)
DECLARE @PractitionerID INT
INSERT @PractitionerList(PracticionerID)
SELECT PracticionerID
FROM Practitioner
WHILE(1 = 1)
BEGIN
SET @PracticionerID = NULL
S...
Set NOW() as Default Value for datetime datatype?
I have two columns in table users namely registerDate and lastVisitDate which consist of datetime data type. I would like to do the following.
...
Why are Oracle table/column/index names limited to 30 characters?
...haracters long. Allowing every line of code that goes something like
l_table_name VARCHAR2(30);
BEGIN
SELECT table_name
INTO l_table_name
FROM dba_tables
WHERE ...
to suddenly break because the DBA 15 years ago used VARCHAR2(30) rather than DBA_TABLES.TABLE_NAME%TYPE in the script...
Disable Laravel's Eloquent timestamps
... we don't want to add the updated_at / created_at fields to all of our tables as we have a logging class that does all this in more depth for us already.
...
How to scroll to the bottom of a UITableView on the iPhone before the view appears
I have a UITableView that is populated with cells of a variable height. I would like the table to scroll to the bottom when the view is pushed into view.
...
List all the files that ever existed in a Git repository
...$ git ff create
A database/migrations/2014_10_12_000000_create_users_table.php
A database/migrations/2014_10_12_100000_create_password_resets_table.php
A database/migrations/2015_05_11_200932_create_boletin_table.php
A database/migrations/2015_05_15_133500_create_usuarios_tab...
Foreign Key to non-primary key
I have a table which holds data, and one of those rows needs to exist in another table. So, I want a foreign key to maintain referential integrity.
...
Oracle: how to UPSERT (update or insert into a table?)
The UPSERT operation either updates or inserts a row in a table, depending if the table already has a row that matches the data:
...