大约有 42,000 项符合查询结果（耗时：0.0387秒） [XML]
Counting null and non-null values in a single query
...a column...
If that is correct:
SELECT count(*) FROM us WHERE a IS NULL
UNION ALL
SELECT count(*) FROM us WHERE a IS NOT NULL
Edited to have the full query, after reading the comments :]
SELECT COUNT(*), 'null_tally' AS narrative
FROM us
WHERE a IS NULL
UNION
SELECT COUNT(*), 'not_null...
PHP - add item to beginning of associative array [duplicate]
...
You could use the union operator:
$arr1 = array('key0' => 'value0') + $arr1;
or array_merge.
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How to log SQL statements in Grails
...6Spy.
B) look at it on database level. For example really easy to do with mysql.
Find out where you general_log_file is. Active general log if no activated already.
mysql command line> show variables like "%general_log%";
mysql command line> set global general_log = true;
Now everything i...
Generating a random & unique 8 character string using MySQL
I'm working on a game which involves vehicles at some point. I have a MySQL table named "vehicles" containing the data about the vehicles, including the column "plate" which stores the License Plates for the vehicles.
...
MYSQL Dump only certain rows
I am trying to do a mysql dump of a few rows in my database. I can then use the dump to upload those few rows into another database. The code I have is working, but it dumps everything. How can I get mysqldump to only dump certain rows of a table?
...
How to work with Git branches and Rails migrations
...'On branch ','').chomp
%>
defaults: &defaults
pool: 5
adapter: mysql2
encoding: utf8
reconnect: false
username: root
password:
host: localhost
<% environments.each do |environment| %>
<%= environment %>:
<<: *defaults
database: <%= [ database_prefix...
Return a value if no rows are found in Microsoft tSQL
...ight be a dead horse, another way to return 1 row when no rows exist is to UNION another query and display results when non exist in the table.
SELECT S.Status, COUNT(s.id) AS StatusCount
FROM Sites S
WHERE S.Id = @SiteId
GROUP BY s.Status
UNION ALL --UNION BACK ON TABLE WITH NOT EXISTS
SELECT 'N/...
Getting raw SQL query string from PDO prepared statements
... prepare(), and the parameters are sent separately when you do execute(). MySQL's general query log does show the final SQL with values interpolated after you execute(). Below is an excerpt from my general query log. I ran the queries from the mysql CLI, not from PDO, but the principle is the sam...
How to randomly select rows in SQL?
...to your question:
Selecting a random row in SQL
Select a random row with MySQL:
SELECT column FROM table
ORDER BY RAND()
LIMIT 1
Select a random row with PostgreSQL:
SELECT column FROM table
ORDER BY RANDOM()
LIMIT 1
Select a random row with Microsoft SQL Server:
SELECT TOP 1 column FROM ta...
+ operator for array in PHP?
...and array)
)
So the logic of + is equivalent to the following snippet:
$union = $array1;
foreach ($array2 as $key => $value) {
if (false === array_key_exists($key, $union)) {
$union[$key] = $value;
}
}
If you are interested in the details of the C-level implementation head t...