SQL Server/T-SQL/Transact SQL/If
Содержание
Conditional Logic IF
18> CREATE TABLE employee (emp_no INTEGER NOT NULL,
19> emp_fname CHAR(20) NOT NULL,
20> emp_lname CHAR(20) NOT NULL,
21> dept_no CHAR(4) NULL)
22>
23> insert into employee values(1, "Matthew", "Smith", "d3")
24> insert into employee values(2, "Ann", "Jones", "d3")
25> insert into employee values(3, "John", "Barrimore","d1")
26> insert into employee values(4, "James", "James", "d2")
27> insert into employee values(5, "Elsa", "Bertoni", "d2")
28> insert into employee values(6, "Elke", "Hansel", "d2")
29> insert into employee values(7, "Sybill", "Moser", "d1")
30>
31> select * from employee
32> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
emp_no emp_fname emp_lname dept_no
----------- -------------------- -------------------- -------
1 Matthew Smith d3
2 Ann Jones d3
3 John Barrimore d1
4 James James d2
5 Elsa Bertoni d2
6 Elke Hansel d2
7 Sybill Moser d1
(7 rows affected)
1>
2> -- Conditional Logic IF
3>
4> CREATE PROCEDURE spTableExists
5> @TableName VarChar(128)
6> AS
7> IF EXISTS(SELECT * FROM sysobjects WHERE name = @TableName)
8> PRINT @TableName + "exists"
9> GO
1>
2> EXEC spTableExists "employee"
3> GO
employeeexists
1>
2> drop procedure spTableExists
3> drop table employee
4> GO
1>
2>
ELSE: execute another line of script when the condition is not met
22>
23> CREATE TABLE employee (emp_no INTEGER NOT NULL,
24> emp_fname CHAR(20) NOT NULL,
25> emp_lname CHAR(20) NOT NULL,
26> dept_no CHAR(4) NULL)
27>
28> insert into employee values(1, "Matthew", "Smith", "d3")
29> insert into employee values(2, "Ann", "Jones", "d3")
30> insert into employee values(3, "John", "Barrimore","d1")
31> insert into employee values(4, "James", "James", "d2")
32> insert into employee values(5, "Elsa", "Bertoni", "d2")
33> insert into employee values(6, "Elke", "Hansel", "d2")
34> insert into employee values(7, "Sybill", "Moser", "d1")
35>
36> select * from employee
37> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
emp_no emp_fname emp_lname dept_no
----------- -------------------- -------------------- -------
1 Matthew Smith d3
2 Ann Jones d3
3 John Barrimore d1
4 James James d2
5 Elsa Bertoni d2
6 Elke Hansel d2
7 Sybill Moser d1
(7 rows affected)
1>
2>
3> -- ELSE: execute another line of script when the condition is not met:
4>
5> CREATE PROCEDURE spTableExists
6> @TableName VarChar(128)
7> AS
8> IF EXISTS(SELECT * FROM sysobjects WHERE name = @TableName)
9> PRINT @TableName + "exists"
10> ELSE
11> PRINT @TableName + "does not"
12> GO
1>
2> EXEC spTableExists "employee"
3> GO
employeeexists
1>
2> drop table employee
3> drop procedure spTableExists
4> GO
1>
2>
IF and else IF
1>
2> CREATE FUNCTION fnFirstName (@FullName VarChar(100)
3> , @FirstOrLast VarChar(5))
4> RETURNS VarChar(100)
5> AS
6> BEGIN
7> DECLARE @CommaPosition Int
8> DECLARE @TheName VarChar(100)
9> IF @FirstOrLast = "First"
10> BEGIN
11> SET @CommaPosition = CHARINDEX(",", @FullName)
12> SET @TheName = SUBSTRING(@FullName, @CommaPosition + 2, LEN(@FullName))
13> END
14> ELSE IF @FirstOrLast = "Last"
15> BEGIN
16> SET @CommaPosition = CHARINDEX(",", @FullName)
17> SET @TheName = SUBSTRING(@FullName, 1, @CommaPosition - 1)
18> END
19> RETURN @TheName
20> END
21> GO
1>
2> SELECT dbo.fnFirstName("Washington, George", "First")
3> GO
----------------------------------------------------------------------------------------
George
(1 rows affected)
1> SELECT dbo.fnFirstName("Washington, George", "Last")
2> GO
----------------------------------------------------------------------------------------
Washington
(1 rows affected)
1>
2> drop function fnFirstName
3> GO
1>
2>
3>
if and else if statement
1>
2>
3> -- Replace the default error message and numbers with my own:
4>
5> CREATE PROCEDURE spRunSQL
6> @Statement VarChar(2000) -- Input param. accepts any SQL statement.
7> AS
8> DECLARE @StartTime DateTime
9> , @EndTime DateTime
10> , @ExecutionTime Int
11> , @ErrNum Int
12> SET @StartTime = GetDate()
13> EXECUTE (@Statement)
14> SET @ErrNum = @@Error
15> IF @ErrNum = 207 -- Bad column
16> RAISERROR 50001 "Bad column name"
17> ELSE IF @ErrNum = 208 -- Bad object
18> RAISERROR 50002 "Bad object name"
19> ELSE IF @ErrNum = 0 -- No error. Resume.
20> BEGIN
21> SET @EndTime = GetDate()
22> SET @ExecutionTime = DateDiff(MilliSecond, @StartTime, @EndTime)
23> RETURN @ExecutionTime -- Return execution time in milliseconds
24> END
25> GO
1>
2> EXEC spRunSQL "select 1 GO"
3> GO
GO
-----------
1
1>
2> EXEC spRunSQL "selet 1 GO"
3> GO
Msg 102, Level 15, State 1, Server sqle\SQLEXPRESS, Line 1
Incorrect syntax near "GO".
1>
2>
3> drop procedure spRunSQL
4> GO
1>
2>
IF and EXISTS function
13> create table Billings (
14> BankerID INTEGER,
15> BillingNumber INTEGER,
16> BillingDate datetime,
17> BillingTotal INTEGER,
18> TermsID INTEGER,
19> BillingDueDate datetime ,
20> PaymentTotal INTEGER,
21> CreditTotal INTEGER
22>
23> );
24> GO
1>
2> INSERT INTO Billings VALUES (1, 1, "2005-01-22", 165, 1,"2005-04-22",123,321);
3> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (2, 2, "2001-02-21", 165, 1,"2002-02-22",123,321.);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (3, 3, "2003-05-02", 165, 1,"2005-04-12",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (4, 4, "1999-03-12", 165, 1,"2005-04-18",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (5, 5, "2000-04-23", 165, 1,"2005-04-17",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (6, 6, "2001-06-14", 165, 1,"2005-04-18",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (7, 7, "2002-07-15", 165, 1,"2005-04-19",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (8, 8, "2003-08-16", 165, 1,"2005-04-20",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (9, 9, "2004-09-17", 165, 1,"2005-04-21",123,321);
2> GO
(1 rows affected)
1> INSERT INTO Billings VALUES (0, 0, "2005-10-18", 165, 1,"2005-04-22",123,321);
2> GO
(1 rows affected)
1>
2>
3> CREATE PROC spInsertBilling
4> @BankerID int, @BillingNumber varchar(50),
5> @BillingDate smalldatetime, @BillingTotal money,
6> @TermsID int, @BillingDueDate smalldatetime
7> AS
8> IF EXISTS(SELECT * FROM Bankers WHERE BankerID = @BankerID)
9> BEGIN
10> INSERT Billings (BankerID)
11> VALUES (@BankerID)
12> END
13> ELSE
14> BEGIN
15> RAISERROR("Not a valid BankerID!",1,1)
16> RETURN -100
17> END
18> GO
1>
2>
3> drop PROC spInsertBilling;
4> GO
1>
2>
3> drop table Billings;
4> GO
If else statement
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int,
5> start_date datetime,
6> city nvarchar (10),
7> region char (1))
8> GO
1>
2> insert into employee (ID, name, salary, start_date, city, region)
3> values (1, "Jason", 40420, "02/01/94", "New York", "W")
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (2, "Robert",14420, "01/02/95", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (3, "Celia", 24020, "12/03/96", "Toronto", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (4, "Linda", 40620, "11/04/97", "New York", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (5, "David", 80026, "10/05/98", "Vancouver","W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (6, "James", 70060, "09/06/99", "Toronto", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (7, "Alison",90620, "08/07/00", "New York", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (8, "Chris", 26020, "07/08/01", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (9, "Mary", 60020, "06/09/02", "Toronto", "W")
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected)
1>
2> drop procedure spInsertDate
3> GO
1>
2> -- The ELSE Clause
3>
4> CREATE PROC spInsertDate
5> @myDate datetime = NULL
6> AS
7> DECLARE @InsertedDate smalldatetime
8>
9> IF DATEDIFF(dd, @myDate, GETDATE()) > 7
10> SELECT @InsertedDate = NULL
11> ELSE
12> SELECT @InsertedDate = CONVERT(datetime,(CONVERT(varchar,@myDate,112)))
13> INSERT INTO Employee (start_date) VALUES ( @InsertedDate)
14> GO
1>
2> EXEC spInsertDate @myDate = "5/1/1999"
3> GO
(1 rows affected)
1>
2> EXEC spInsertDate @myDate = "10/10/2006"
3> GO
(1 rows affected)
1>
2>
3> select * from Employee
4> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
NULL NULL NULL NULL NULL NULL
NULL NULL NULL 2006-10-10 00:00:00.000 NULL NULL
(11 rows affected)
1>
2> drop table employee
3> GO
1>
If statement
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int,
5> start_date datetime,
6> city nvarchar (10),
7> region char (1))
8> GO
1>
2> insert into employee (ID, name, salary, start_date, city, region)
3> values (1, "Jason", 40420, "02/01/94", "New York", "W")
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (2, "Robert",14420, "01/02/95", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (3, "Celia", 24020, "12/03/96", "Toronto", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (4, "Linda", 40620, "11/04/97", "New York", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (5, "David", 80026, "10/05/98", "Vancouver","W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (6, "James", 70060, "09/06/99", "Toronto", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (7, "Alison",90620, "08/07/00", "New York", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (8, "Chris", 26020, "07/08/01", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (9, "Mary", 60020, "06/09/02", "Toronto", "W")
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected)
1>
2>
3> -- Control-of-Flow Statements
4>
5> CREATE PROC spInsertDate
6> @myDate datetime = NULL
7> AS
8> IF DATEDIFF(dd, @myDate, GETDATE()) > 7
9> SELECT @myDate = NULL
10> INSERT INTO Employee (start_date) VALUES (@myDate)
11> GO
1>
2> EXEC spInsertDate @myDate = "5/1/1999"
3> GO
(1 rows affected)
1>
2> EXEC spInsertDate @myDate = "10/10/2006"
3> GO
(1 rows affected)
1>
2> SELECT * FROM Employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
NULL NULL NULL NULL NULL NULL
NULL NULL NULL 2006-10-10 00:00:00.000 NULL NULL
(11 rows affected)
1>
2> drop table employee
3> GO
1>