大约有 43,000 项符合查询结果（耗时：0.0234秒） [XML]
Table name as variable
...mpare data between the same tables of different databases:
static query:
SELECT * FROM [DB_ONE].[dbo].[ACTY]
EXCEPT
SELECT * FROM [DB_TWO].[dbo].[ACTY]
since I want easily change tha name of table and schema I have created this dynamic query:
declare @schema varchar(50)
declare @table varchar(5...
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
...
Get record counts for all tables in MySQL database
...get the count of rows in all tables in a MySQL database without running a SELECT count() on each table?
19 Answers
...
How do SQL EXISTS statements work?
... criteria -- this is why it can be faster than IN. Also be aware that the SELECT clause in an EXISTS is ignored - IE:
SELECT s.*
FROM SUPPLIERS s
WHERE EXISTS (SELECT 1/0
FROM ORDERS o
WHERE o.supplier_id = s.supplier_id)
...should hit a division by zero error...
Drop all the tables, stored procedures, triggers, constraints and all the dependencies in one sql st
...stem stored procs */
DECLARE @name VARCHAR(128)
DECLARE @SQL VARCHAR(254)
SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'P' AND category = 0 ORDER BY [name])
WHILE @name is not null
BEGIN
SELECT @SQL = 'DROP PROCEDURE [dbo].[' + RTRIM(@name) +']'
EXEC (@SQL)
PRINT ...
SELECT DISTINCT on one column
...ou're on SQL Server 2005 or greater, you can use a CTE with ROW_NUMBER():
SELECT *
FROM (SELECT ID, SKU, Product,
ROW_NUMBER() OVER (PARTITION BY PRODUCT ORDER BY ID) AS RowNumber
FROM MyTable
WHERE SKU LIKE 'FOO%') AS a
WHERE a.RowNumber = 1
...
How to select all records from one table that do not exist in another table?
...
SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 wi...
how to listen to N channels? (dynamic select statement)
...
You can do this using the Select function from the reflect package:
func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool)
Select executes a select operation described by the list of cases. Like
the Go select statement, it bl...
How to ensure a form field is submitted when it is disabled?
I have a select form field that I want to mark as "readonly", as in the user cannot modify the value, but the value is still submitted with the form. Using the disabled attribute prevents the user from changing the value, but does not submit the value with the form.
...
how do I query sql for a latest record date for each user
...
select t.username, t.date, t.value
from MyTable t
inner join (
select username, max(date) as MaxDate
from MyTable
group by username
) tm on t.username = tm.username and t.date = tm.MaxDate
...