大约有 44,000 项符合查询结果（耗时：0.0298秒） [XML]
How to declare a variable in a PostgreSQL query
...ows you to return a table of temporary values.
WITH master_user AS (
SELECT
login,
registration_date
FROM users
WHERE ...
)
SELECT *
FROM users
WHERE master_login = (SELECT login
FROM master_user)
AND (SELECT registration_date
FROM ma...
How to best display in Terminal a MySQL SELECT returning too many fields?
...
Terminate the query with \G in place of ;. For example:
SELECT * FROM sometable\G
This query displays the rows vertically, like this:
*************************** 1. row ***************************
Host: localhost
Db: mydatabase1
...
How to delete duplicates on a MySQL table?
...n an index is going to be slow for large tables. Wouldn't it be better to SELECT MAX(ID) FROM t GROUP BY unique and then JOIN to an exact match of ID to MAX(ID)?
– ebyrob
Nov 10 '16 at 16:31
...
Linq: What is the difference between Select and Where
The Select and Where methods are available in Linq. What should every developer know about these two methods? For example: when to use one over the other, any advantages of using one over the other, etc.
...
How do I split a string so I can access item x?
...0,
PATINDEX('%|%', @products))
SELECT @individual
SET @products = SUBSTRING(@products,
LEN(@individual + '|') + 1,
LEN(@products))
END
ELSE
BEGIN
SET @individu...
In MySQL, can I copy one row to insert into the same table?
...e) but I want to do this without having to list all the columns after the "select", because this table has too many columns.
...
How can I disable the UITableView selection?
When you tap a row in a UITableView , the row is highlighted and selected. Is it possible to disable this so tapping a row does nothing?
...
Counting null and non-null values in a single query
...le and SQL Server (you might be able to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
...
Find rows that have the same value on a column in MySQL
...sses and how many times they're used, with the most used addresses first.
SELECT email,
count(*) AS c
FROM TABLE
GROUP BY email
HAVING c > 1
ORDER BY c DESC
If you want the full rows:
select * from table where email in (
select email from table
group by email having count(*) &g...
How can I add an item to a SelectList in ASP.net MVC
Basically I am looking to insert an item at the beginning of a SelectList with the default value of 0 and the Text Value of " -- Select One --"
...