大约有 41,000 项符合查询结果（耗时：0.0454秒） [XML]
add column to mysql table if it does not exist
...rade_database_1_0_to_2_0()
BEGIN
-- rename a table safely
IF NOT EXISTS( (SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE()
AND TABLE_NAME='my_old_table_name') ) THEN
RENAME TABLE
my_old_table_name TO my_new_table_name,
END IF;
-- add a column safely
IF NO...
Is there a JSON equivalent of XQuery/XPath?
...g
tools including filtering, recursive search, sorting, mapping, range
selection, and flexible expressions with wildcard string comparisons
and various operators.
JSONselect has another point of view on the question (CSS selector-like, rather than XPath) and has a JavaScript implementation.
...
Rename MySQL database [duplicate]
...be found using a
query on information_schema.TABLES table.
mysql> select TABLE_NAME from information_schema.tables where
table_schema='<old_schema_name>' and TABLE_TYPE='BASE TABLE';
3) Dump the views in an out file. Views can be found using a query on
the same information_...
What are best practices for multi-language database design? [closed]
... you might be thinking, that instead of writing simple queries like this:
SELECT price, name, description FROM Products WHERE price < 100
...you would need to start writing queries like that:
SELECT
p.price, pt.name, pt.description
FROM
Products p JOIN ProductTranslations pt
ON (p.id = ...
Correct way to pass multiple values for same parameter name in GET request
...s handle forms by default. For example take a look at the form element <select multiple> and how it handles multiple values from this example at w3schools.
<form action="/action_page.php">
<select name="cars" multiple>
<option value="volvo">Volvo</option>
<optio...
Running JAR file on Windows
...e Environment (JRE).
Or this:
Open the Windows Explorer, from the Tools select 'Folder Options...'
Click the File Types tab, scroll down and select JAR File type.
Press the Advanced button.
In the Edit File Type dialog box, select open in Actions box and click Edit...
Press the Browse button and ...
Paste multiple times
...
Clever. 'p' to paste, 'gv' to re-select what was originally selected. 'y' to copy it again.
– Amjith
Aug 23 '11 at 21:17
...
How to enable MySQL Query Log?
...global general_log = 1;
SET global log_output = 'table';
View the log
select * from mysql.general_log;
Disable Query logging on the database
SET global general_log = 0;
share
|
improve th...
How to find the mysql data directory from command line in windows
... the following command line:
mysql -s -N -uUSER -p information_schema -e 'SELECT Variable_Value FROM GLOBAL_VARIABLES WHERE Variable_Name = "datadir"'
The command will select the value only from mysql's internal information_schema database and disables the tabular output and column headers.
Outp...
Difference between UTF-8 and UTF-16?
...
Both UTF-8 and UTF-16 are variable length encodings. However, in UTF-8 a character may occupy a minimum of 8 bits, while in UTF-16 character length starts with 16 bits.
Main UTF-8 pros:
Basic ASCII characters like digits, Latin characters with no accents, etc. occupy one byte which is identical...