大约有 47,000 项符合查询结果（耗时：0.0348秒） [XML]
NOT IN vs NOT EXISTS
...llow NULLs the NOT IN will be treated identically to the following query.
SELECT ProductID,
ProductName
FROM Products p
WHERE NOT EXISTS (SELECT *
FROM [Order Details] od
WHERE p.ProductId = od.ProductId)
The exact plan may vary but for my examp...
How to search a specific value in all tables (PostgreSQL)?
... If you're using IntelliJ you can just right-click your db and select "Dump with 'pg_dump'" or "Dump data to file(s)"
– Laurens
Nov 29 '17 at 12:26
3
...
MySQL ON vs USING?
...n tables ON a column, a set of columns and even a condition. For example:
SELECT * FROM world.City JOIN world.Country ON (City.CountryCode = Country.Code) WHERE ...
USING is useful when both tables share a column of the exact same name on which they join. In this case, one may say:
SELECT ... FR...
selecting unique values from a column
...
Use the DISTINCT operator in MySQL:
SELECT DISTINCT(Date) AS Date FROM buy ORDER BY Date DESC;
share
|
improve this answer
|
follow
...
How do you select a particular option in a SELECT element in jQuery?
...
A selector to get the middle option-element by value is
$('.selDiv option[value="SEL1"]')
For an index:
$('.selDiv option:eq(1)')
For a known text:
$('.selDiv option:contains("Selection 1")')
EDIT: As commented above t...
ROW_NUMBER() in MySQL
...asy, but actually it kind of isn't).
I often plump for a null-self-join:
SELECT t0.col3
FROM table AS t0
LEFT JOIN table AS t1 ON t0.col1=t1.col1 AND t0.col2=t1.col2 AND t1.col3>t0.col3
WHERE t1.col1 IS NULL;
“Get the rows in the table for which no other row with matching col1,col2 has a hi...
Preventing an image from being draggable or selectable without using JS
Does anyone know of a way to make an image not draggable and not selectable -- at the same time -- in Firefox, without resorting to Javascript? Seems trivial, but here's the issue:
...
how to exclude null values in array_agg like in string_agg using postgres?
...
SQL Fiddle
select
id,
(select array_agg(a) from unnest(canonical_users) a where a is not null) canonical_users,
(select array_agg(a) from unnest(non_canonical_users) a where a is not null) non_canonical_users
from (
SELE...
Programmatically select text in a contenteditable HTML element?
In JavaScript, it's possible to programmatically select text in an input or textarea element. You can focus an input with ipt.focus() , and then select its contents with ipt.select() . You can even select a specific range with ipt.setSelectionRange(from,to) .
...
MySQL LIKE IN()?
... might be more efficient, but you'd have to benchmark it to be sure, e.g.
SELECT * from fiberbox where field REGEXP '1740|1938|1940';
share
|
improve this answer
|
follow
...