System Functions1. String functionsa. substringb. rightc.
upperd. lowere. charindex f. patindex g. ascii h. chari. ltrim j.
rtrim k. spacel. str m. soundex n. replicate2. Date convert
functionsEg : select convert(varchar(8),pubdate,2) from titles
where title_id = 'MC3026a. 2yy.mm.dd b. 3dd/mm/yy c. 4dd.mm.yy d.
5dd-mm-yy e. 102yyyy.mm.dd f. 103dd/mm/yyyy g. 104dd.mm.yyyy h.
105dd-mm-yyyy 3. Date functionsa. datename b. datepart c. dateadd
d. datediff 4. Maths functionsa. absb. ceilingc. floord. rounde.
expf. randg. logh. pii. powerj. sqrt k. sinl. cos m. tan5. ISNULL6.
COALESCE
User defined Functions
1. User-Defined FunctionEG : CREATE FUNCTION whichContinent
(@Country nvarchar(15))RETURNS varchar(30)ASBEGINdeclare @Return
varchar(30)select @return = case @Countrywhen 'Argentina' then
'South America'when 'Belgium' then 'Europe'when 'Brazil' then
'South America'when 'Canada' then 'North America'when 'Denmark'
then 'Europe'when 'Finland' then 'Europe'when 'France' then
'Europe'else 'Unknown'end
return @returnend
--/// you can use the functions inside the column name
print dbo.WhichContinent('USA')
select dbo.WhichContinent(Customers.Country), customers.* from
customers
create table test(Country varchar(15),Continent as
(dbo.WhichContinent(Country)))
insert into test (country) values ('USA')
select * from test
2. Inline Table-Value
CREATE FUNCTION CustomersByContinent (@Continent
varchar(30))RETURNS TABLE ASRETURN SELECT
dbo.WhichContinent(Customers.Country) as continent, customers.*
FROM customers WHERE dbo.WhichContinent(Customers.Country) =
@ContinentGO
SELECT * from CustomersbyContinent('North America')SELECT * from
CustomersByContinent('South America')SELECT * from
customersbyContinent('Unknown')
3. Multi-statement Table-Value
CREATE FUNCTION dbo.customersbycountry ( @Country varchar(15)
)RETURNS @CustomersbyCountryTab table ([CustomerID] [nchar] (5),
[CompanyName] [nvarchar] (40), [ContactName] [nvarchar] (30),
[ContactTitle] [nvarchar] (30), [Address] [nvarchar] (60), [City]
[nvarchar] (15),[PostalCode] [nvarchar] (10), [Country] [nvarchar]
(15), [Phone] [nvarchar] (24), [Fax] [nvarchar] (24))ASBEGININSERT
INTO @CustomersByCountryTab SELECT [CustomerID], [CompanyName],
[ContactName], [ContactTitle], [Address], [City], [PostalCode],
[Country], [Phone], [Fax] FROM [Northwind].[dbo].[Customers]WHERE
country = @CountryDECLARE @cnt INTSELECT @cnt = COUNT(*) FROM
@customersbyCountryTabIF @cnt = 0INSERT INTO @CustomersByCountryTab
([CustomerID],[CompanyName],[ContactName],[ContactTitle],[Address],[City],[PostalCode],[Country],
[Phone],[Fax] )VALUES ('','No Companies
Found','','','','','','','','')RETURNENDGOSELECT * FROM
dbo.customersbycountry('USA')SELECT * FROM
dbo.customersbycountry('CANADA')SELECT * FROM
dbo.customersbycountry('ADF')
