大约有 40,000 项符合查询结果（耗时：0.0412秒） [XML]
How to test an SQL Update statement before running it?
...yway) you can also do a sanity check which rows are affected by running a select using the same WHERE clause as the UPDATE.
So if you UPDATE is
UPDATE foo
SET bar = 42
WHERE col1 = 1
AND col2 = 'foobar';
The following will show you which rows will be updated:
SELECT *
FROM foo
WHERE col1 ...
How to detect when cancel is clicked on file input?
...s not exposed to the browser." This is not true if the dialog is closed by selecting a file.
– Trevor
Dec 1 '16 at 22:24
...
Regex select all text between tags
What is the best way to select all the text between 2 tags - ex: the text between all the 'pre' tags on the page.
17 Answe...
tmux set -g mouse-mode on doesn't work
...n. There's now no longer options for:
- mouse-resize-pane
- mouse-select-pane
- mouse-select-window
- mode-mouse
Instead there is just one option: 'mouse' which turns on mouse support
So this is what I'm using now in my .tmux.conf file
set -g mouse on
...
Row count with PDO
...
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query...
How to change options of with jQuery?
Suppose a list of options is available, how do you update the <select> with new <option> s?
9 Answers
...
PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
INNER JOIN ON vs WHERE clause
...ed is a cartesian product of the tables to which a filter is applied which selects only those rows with joining columns matching.
It's easier to see this with the WHERE syntax.
As for your example, in MySQL (and in SQL generally) these two queries are synonyms.
Also note that MySQL also has a STR...
Finding duplicate values in MySQL
...
Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:
SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;
This will return a result with the name value in the first colum...
List of all index & index columns in SQL Server DB
...lumns.
EDIT: This query's getting pretty close to what you're looking for:
SELECT
TableName = t.name,
IndexName = ind.name,
IndexId = ind.index_id,
ColumnId = ic.index_column_id,
ColumnName = col.name,
ind.*,
ic.*,
col.*
FROM
sys.indexes ind
INNER JOI...