SQL Server/T-SQL Tutorial/Transact SQL/Declare — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 10:22, 26 мая 2010
Содержание
- 1 Declare a table type variable and query it
- 2 DECLARE @Out Int
- 3 DECLARE @Out Int (get value out of a procedure)
- 4 It is possible to define several variables in a single Declare statement.
- 5 Simple SELECT query written using variables for field names.
- 6 The DECLARE statement has a pretty simple syntax:
- 7 The names of variables must begin with @
Declare a table type variable and query it
7> CREATE TABLE Orders (
8> OrderID int NOT NULL ,
9> CustomerID nchar (5) NULL ,
10> EmployeeID int NULL ,
11> OrderDate datetime NULL ,
12> RequiredDate datetime NULL ,
13> ShippedDate datetime NULL ,
14> ShipVia int NULL ,
15> Freight money NULL DEFAULT (0),
16> ShipName nvarchar (40) NULL ,
17> ShipAddress nvarchar (60) NULL ,
18> ShipCity nvarchar (15) NULL ,
19> ShipRegion nvarchar (15) NULL ,
20> ShipPostalCode nvarchar (10) NULL ,
21> ShipCountry nvarchar (15) NULL
22> )
23> GO
1>
2> DECLARE @MyTable Table
3> (
4> OrderID int,
5> CustomerID char(5)
6> )
7>
8> INSERT INTO @MyTable
9> SELECT OrderID, CustomerID
10> FROM Orders
11> WHERE OrderID BETWEEN 10240 AND 10250
12>
13> SELECT *
14> FROM @MyTable
15> GO
(0 rows affected)
OrderID CustomerID
----------- ----------
(0 rows affected)
1>
2> drop table orders;
3> GO
1>
DECLARE @Out Int
3>
4>
5>
6> CREATE TABLE Product(
7> ProductID int NOT NULL,
8> Name nvarchar(25) NOT NULL,
9> ProductNumber nvarchar(25) ,
10> Color nvarchar(15) NULL,
11> StandardCost money NOT NULL,
12> Size nvarchar(5) NULL,
13> Weight decimal(8, 2) NULL,
14> ProductLine nchar(20) NULL,
15> SellStartDate datetime NOT NULL,
16> SellEndDate datetime NULL
17> )
18> GO
1> insert into Product values(1,"Product A", "1","Red",123.123,"1",1,"ProductLine A","1999-03-22","2000-03-22");
2> GO
(1 rows affected)
1> insert into Product values(2,"Product B", "2","Yellow",234.234,"1",3,"ProductLine B","2000-03-22","2001-03-22");
2> GO
(1 rows affected)
1> insert into Product values(3,"Product C", "3","Pink",345.345,"1",3,"ProductLine V","2001-09-22","2006-02-22");
2> GO
(1 rows affected)
1> insert into Product values(4,"Product D", "4","White",456.456,"1",4,"ProductLine D","2002-08-22","2006-03-22");
2> GO
(1 rows affected)
1> insert into Product values(5,"Product E", "5","Black",567.567,"1",5,"ProductLine E","2003-01-22","2003-04-22");
2> GO
(1 rows affected)
1> insert into Product values(6,"Product F", "6","Blue",678.678,"1",6,"ProductLine W","2004-02-22","2005-05-22");
2> GO
(1 rows affected)
1> insert into Product values(7,"Product G", "7","Drak",789.789,"1",7,"ProductLine Q","2005-03-22","2006-03-22");
2> GO
(1 rows affected)
1> insert into Product values(8,"Product H", "8","Gray",234.123,"1",8,"ProductLine F","2006-04-22","2006-09-22");
2> GO
(1 rows affected)
1> insert into Product values(9,"Product I", "9","Red",543.123,"1",9,"ProductLine R","2007-05-22","2008-03-22");
2> GO
(1 rows affected)
1> insert into Product values(0,"Product J", "0","Gold",765.123,"1",0,"ProductLine J","2008-06-22","2009-03-22");
2> GO
(1 rows affected)
1>
2>
3>
4> CREATE PROCEDURE spProductCountBySubCategory
5> @SubID Int,
6> @ProdCount Int OUTPUT
7> AS
8> SELECT @ProdCount = COUNT(*)
9> FROM Product
10> WHERE ProductID = @SubID
11> GO
1>
2> DECLARE @Out Int
3>
4> EXECUTE spProductCountBySubCategory
5> @SubID = 2,
6> @ProdCount = @Out
7>
8>
9> SELECT @Out AS ProductCountBySubCategory
10> GO
ProductCountBySubCategory
-------------------------
NULL
(1 rows affected)
1>
2> drop PROCEDURE spProductCountBySubCategory;
3> GO
1>
2>
3> drop table Product;
4> GO
1>
DECLARE @Out Int (get value out of a procedure)
6> CREATE TABLE Product(
7> ProductID int NOT NULL,
8> Name nvarchar(25) NOT NULL,
9> ProductNumber nvarchar(25) ,
10> Color nvarchar(15) NULL,
11> StandardCost money NOT NULL,
12> Size nvarchar(5) NULL,
13> Weight decimal(8, 2) NULL,
14> ProductLine nchar(20) NULL,
15> SellStartDate datetime NOT NULL,
16> SellEndDate datetime NULL
17> )
18> GO
1> insert into Product values(1,"Product A", "1","Red",123.123,"1",1,"ProductLine A","1999-03-22","2000-03-22");
2> GO
(1 rows affected)
1>
2>
3> insert into Product values(2,"Product B", "2","Yellow",234.234,"1",3,"ProductLine B","2000-03-22","2001-03-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(3,"Product C", "3","Pink",345.345,"1",3,"ProductLine V","2001-09-22","2006-02-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(4,"Product D", "4","White",456.456,"1",4,"ProductLine D","2002-08-22","2006-03-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(5,"Product E", "5","Black",567.567,"1",5,"ProductLine E","2003-01-22","2003-04-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(6,"Product F", "6","Blue",678.678,"1",6,"ProductLine W","2004-02-22","2005-05-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(7,"Product G", "7","Drak",789.789,"1",7,"ProductLine Q","2005-03-22","2006-03-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(8,"Product H", "8","Gray",234.123,"1",8,"ProductLine F","2006-04-22","2006-09-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(9,"Product I", "9","Red",543.123,"1",9,"ProductLine R","2007-05-22","2008-03-22");
4> GO
(1 rows affected)
1>
2>
3> insert into Product values(0,"Product J", "0","Gold",765.123,"1",0,"ProductLine J","2008-06-22","2009-03-22");
4> GO
(1 rows affected)
1>
2>
3>
4>
5>
6> CREATE PROCEDURE spProductCountBySubCategory
7> @SubID Int,
8> @ProdCount Int OUTPUT
9> AS
10> SELECT @ProdCount = COUNT(*)
11> FROM Product
12> WHERE ProductID = @SubID
13> GO
1>
2> DECLARE @Out Int
3>
4> EXECUTE spProductCountBySubCategory
5> @SubID = 2,
6> @ProdCount = @Out
7>
8>
9> SELECT @Out AS ProductCountBySubCategory
10> GO
ProductCountBySubCategory
-------------------------
NULL
(1 rows affected)
1>
2> drop PROCEDURE spProductCountBySubCategory;
3> GO
1>
2>
3> drop table Product;
4> GO
1>
It is possible to define several variables in a single Declare statement.
4>
5>
6> Declare @LastName varchar(50),
7> @FirstName varchar(20),
8> @BirthDate smalldatetime
9> GO
1>
Simple SELECT query written using variables for field names.
3>
4>
5> CREATE TABLE authors(
6> au_id varchar(11),
7> au_lname varchar(40) NOT NULL,
8> au_fname varchar(20) NOT NULL,
9> phone char(12) NOT NULL DEFAULT ("UNKNOWN"),
10> address varchar(40) NULL,
11> city varchar(20) NULL,
12> state char(2) NULL,
13> zip char(5) NULL,
14> contract bit NOT NULL
15> )
16> GO
1> insert authors values("1", "Joe", "Abra", "111 111-1111", "6 St.", "Berkeley", "CA", "11111", 1)
2> insert authors values("2", "Jack", "Majo", "222 222-2222", "3 St.", "Oakland" , "CA", "22222", 1)
3> insert authors values("3", "Pink", "Cherry", "333 333-3333", "5 Ln.", "Vancouver", "BC", "33333", 1)
4> insert authors values("4", "Blue", "Albert", "444 444-4444", "7 Av.", "Vancouver", "BC", "44444", 1)
5> insert authors values("5", "Red", "Anne", "555 555-5555", "6 Av.", "Regina", "SK", "55555", 1)
6> insert authors values("6", "Black", "Michel", "666 666-6666", "3 Pl.", "Regina", "SK", "66666", 1)
7> insert authors values("7", "White", "Sylvia", "777 777-7777", "1 Pl.", "Rockville", "MD", "77777", 1)
8> insert authors values("8", "Yellow","Heather","888 888-8888", "3 Pu", "Vacaville", "CA", "88888", 0)
9> insert authors values("9", "Gold", "Dep", "999 999-9999", "5 Av.", "Oakland", "CA", "99999", 0)
10> insert authors values("10", "Siler", "Dean", "000 000-0000", "4 Av.", "Oakland", "CA", "00000", 1)
11> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2>
3> DECLARE @chvField1 VARCHAR(30),
4> @chvField2 VARCHAR(30),
5> @chvSQL VARCHAR(255)
6> SELECT @chvField1 = "au_fname"
7> SELECT @chvField2 = "au_lname"
8> SELECT @chvSQL = "SELECT " + @chvField1 + ", " + @chvField2 + " FROM authors"
9> EXEC (@chvSQL)
10> GO
au_fname au_lname
-------------------- ----------------------------------------
Abra Joe
Majo Jack
Cherry Pink
Albert Blue
Anne Red
Michel Black
Sylvia White
Heather Yellow
Dep Gold
Dean Siler
(10 rows affected)
1>
2> drop table authors;
3> GO
1>
The DECLARE statement has a pretty simple syntax:
5> --DECLARE @<variable name> <variable type>[,
6> -- @<variable name> <variable type>[,
7> -- @<variable name> <variable type>]]
8> --
9> --Setting Variables Using SET
10>
11>
12> CREATE TABLE OrderDetails (
13> OrderID int NOT NULL ,
14> ProductID int NOT NULL ,
15> UnitPrice money NOT NULL DEFAULT (0),
16> Quantity smallint NOT NULL DEFAULT (1),
17> Discount real NOT NULL DEFAULT (0)
18> )
19> GO
1> INSERT OrderDetails VALUES(10248,11,14,12,0)
2> INSERT OrderDetails VALUES(10248,42,9.8,10,0)
3> INSERT OrderDetails VALUES(10248,72,34.8,5,0)
4> INSERT OrderDetails VALUES(10249,14,18.6,9,0)
5> INSERT OrderDetails VALUES(10249,51,42.4,40,0)
6> INSERT OrderDetails VALUES(10250,41,7.7,10,0)
7> INSERT OrderDetails VALUES(10250,51,42.4,35,0.15)
8> INSERT OrderDetails VALUES(10250,65,16.8,15,0.15)
9> INSERT OrderDetails VALUES(10251,22,16.8,6,0.05)
10> INSERT OrderDetails VALUES(10251,57,15.6,15,0.05)
11> go
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2> DECLARE @TotalCost money
3>
4> SET @TotalCost = 10
5> SET @TotalCost = @TotalCost * 1.1
6>
7>
8> DECLARE @Test money
9>
10> select @Test = MAX(UnitPrice) FROM OrderDetails
11> SELECT @Test
12> GO
---------------------
42.4000
(1 rows affected)
1>
2> drop table OrderDetails;
3> GO
The names of variables must begin with @
5>
6> Declare @LastName varchar(50)
7> GO
1>