如何在SQL SELECT语句中执行IF…THEN?
例如:
SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product
如何在SQL SELECT语句中执行IF…THEN?
例如:
SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product
当前回答
SELECT CASE WHEN Obsolete = 'N' or InStock = 'Y' THEN 1 ELSE 0
END AS Saleable, *
FROM Product
其他回答
会是这样的:
SELECT OrderID, Quantity,
CASE
WHEN Quantity > 30 THEN "The quantity is greater than 30"
WHEN Quantity = 30 THEN "The quantity is 30"
ELSE "The quantity is under 30"
END AS QuantityText
FROM OrderDetails;
case statement some what similar to if in SQL server
SELECT CASE
WHEN Obsolete = 'N' or InStock = 'Y'
THEN 1
ELSE 0
END as Saleable, *
FROM Product
SQL Server 2012中添加了一个新功能IIF(我们可以简单使用):
SELECT IIF ( (Obsolete = 'N' OR InStock = 'Y'), 1, 0) AS Saleable, * FROM Product
SQL Server中的简单if-else语句:
DECLARE @val INT;
SET @val = 15;
IF @val < 25
PRINT 'Hi Ravi Anand';
ELSE
PRINT 'By Ravi Anand.';
GO
SQL Server中嵌套的If…else语句-
DECLARE @val INT;
SET @val = 15;
IF @val < 25
PRINT 'Hi Ravi Anand.';
ELSE
BEGIN
IF @val < 50
PRINT 'what''s up?';
ELSE
PRINT 'Bye Ravi Anand.';
END;
GO
Microsoft SQL Server(T-SQL)
在选择中,使用:
select case when Obsolete = 'N' or InStock = 'Y' then 'YES' else 'NO' end
在where子句中,使用:
where 1 = case when Obsolete = 'N' or InStock = 'Y' then 1 else 0 end