sql - NOT IN vs NOT EXISTS - Stack Overflow
Which of these queries is the faster? NOT EXISTS: SELECT ProductID, ProductName FROM Northwind..Products p WHERE NOT EXISTS ( SELECT 1 FROM Northwind..[Order Details] od …
What does the "@" symbol do in SQL? - Stack Overflow
The @CustID means it's a parameter that you will supply a value for later in your code. This is the best way of protecting against SQL injection. Create your query using parameters, rather than …
How do I perform an IF...THEN in an SQL SELECT?
2008年9月15日 · The CASE statement is the closest to IF in SQL and is supported on all versions of SQL Server.
SQL: IF clause within WHERE clause - Stack Overflow
2008年9月18日 · Is it possible to use an IF clause within a WHERE clause in MS SQL? Example: WHERE IF IsNumeric(@OrderNumber) = 1 OrderNumber = @OrderNumber ELSE OrderNumber …
SQL to find the number of distinct values in a column
2019年4月5日 · SQL to find the number of distinct values in a column Asked 17 years, 2 months ago Modified 2 years, 8 months ago Viewed 826k times
sql - Efficiently convert rows to columns - Stack Overflow
I'm looking for an efficient way to convert rows to columns in SQL Server, I heard that PIVOT is not very fast, and I need to deal with lot of records. This is my example: Id Value ColumnName 1 John
Login to Microsoft SQL Server Error: 18456 - Stack Overflow
2016年7月8日 · I am getting this error while trying to connect to the SQL Server. Microsoft SQL Server Error: 18456 Can anybody tell me what the error code means?
Get the last day of the month in SQL - Stack Overflow
From SQL Server 2012 you can use the EOMONTH function. Returns the last day of the month that contains the specified date, with an optional offset. Syntax
sql - Concatenate text from multiple rows into a single text string ...
Consider a database table holding names, with three rows: Peter Paul Mary Is there an easy way to turn this into a single string of Peter, Paul, Mary?
sql - What is the difference between JOIN and INNER JOIN ... - Stack ...
SELECT * FROM table INNER JOIN otherTable ON table.ID = otherTable.FK Is there any difference between the statements in performance or otherwise? Does it differ between different SQL …