COALESCE 函数
1 SET NOCOUNT ON; 2 GO 3 USE tempdb; 4 IF OBJECT_ID(\'dbo.wages\') IS NOT NULL 5 DROP TABLE wages; 6 GO 7 CREATE TABLE dbo.wages 8 ( 9 emp_id tinyint identity, 10 hourly_wage decimal NULL, 11 salary decimal NULL, 12 commission decimal NULL, 13 num_sales tinyint NULL 14 ); 15 GO 16 INSERT dbo.wages (hourly_wage, salary, commission, num_sales) 17 VALUES 18 (10.00, NULL, NULL, NULL), 19 (20.00, NULL, NULL, NULL), 20 (30.00, NULL, NULL, NULL), 21 (40.00, NULL, NULL, NULL), 22 (NULL, 10000.00, NULL, NULL), 23 (NULL, 20000.00, NULL, NULL), 24 (NULL, 30000.00, NULL, NULL), 25 (NULL, 40000.00, NULL, NULL), 26 (NULL, NULL, 15000, 3), 27 (NULL, NULL, 25000, 2), 28 (NULL, NULL, 20000, 6), 29 (NULL, NULL, 14000, 4); 30 GO 31 SET NOCOUNT OFF; 32 GO 33 SELECT CAST(COALESCE(hourly_wage * 40 * 52, salary,commission * num_sales) AS money) AS \'Total Salary\' 34 FROM dbo.wages 35 ORDER BY \'Total Salary\'; 36 GO 37 --COALESCE(Class, Color, ProductNumber) AS FirstNotNull 38 39 40 select coalesce(hourly_wage, salary, commission, num_sales) as ds from dbo.wages 41 select coalesce(hourly_wage, salary, commission) as ds from dbo.wages 42 select * from dbo.wages 43 select coalesce(hourly_wage,num_sales) as ds from dbo.wages 44 select * from dbo.wages