大约有 37,000 项符合查询结果（耗时：0.0332秒） [XML]
Postgresql query between date ranges
...= 2
This involves calculating the conditions for every single row in the table (a scan) and not using index to find the range of rows that will match (a range-seek).
share
|
improve this answer
...
Oracle SQL Query for listing all Schemas in a DB
...le mean it's a user ? I mean a schema = user ? and under that user all the tables created same like MySQL ?
– Osama Al-Banna
Jun 15 '16 at 14:12
add a comment
...
Detect if value is number in MySQL
...
This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
share
|
...
Query to list all stored procedures
...m my understanding the "preferred" method is to use the information_schema tables:
select *
from information_schema.routines
where routine_type = 'PROCEDURE'
share
|
improve this answer
...
Understanding “randomness”
...et after multiplying two random variables:
BarChart[BinCounts[Table[RandomReal[{0, 1}, 50000] *
RandomReal[{0, 1}, 50000], {50000}], 0.01]]
So, both are “random”, but their distribution is very different.
Another example
While 2 * Random() is un...
How to use GROUP BY to concatenate strings in MySQL?
...
SELECT id, GROUP_CONCAT(name SEPARATOR ' ') FROM table GROUP BY id;
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
From the link above, GROUP_CONCAT: This function returns a string result with the concatenated non-NULL values from a ...
How to set the UITableView Section title programmatically (iPhone/iPad)?
I've created a UITableView in Interface Builder using storyboards . The UITableView is setup with static cells and a number of different sections.
...
How to find out the MySQL root password
... did the following:
sudo service mysql stop
sudo mysqld_safe --skip-grant-tables --skip-syslog --skip-networking
Then run mysql in a new terminal:
mysql -u root
And run the following queries to change the password:
UPDATE mysql.user SET authentication_string=PASSWORD('password') WHERE User='r...
How do I update if exists, insert if not (AKA “upsert” or “merge”) in MySQL?
... @blub: If you create a unique key on geb and topic it will work (ALTER TABLE table ADD UNIQUE geb_by_topic (geb, topic)).
– chaos
Aug 2 '09 at 13:43
1
...
HTML5 LocalStorage: Checking if a key exists [duplicate]
...'s worth noting that the constraints FF (28.0) imposes on its localStorage table allows null values: CREATE TABLE webappsstore2 (scope TEXT, key TEXT, value TEXT, secure INTEGER, owner TEXT) while Chrome does not: CREATE TABLE ItemTable (key TEXT UNIQUE ON CONFLICT REPLACE, value BLOB NOT NULL ON CO...