IF EXISTS : IF « Transact SQL « SQL Server / T-SQL Tutorial






7>
8> CREATE TABLE employee(
9>    id          INTEGER NOT NULL PRIMARY KEY,
10>    first_name  VARCHAR(10),
11>    last_name   VARCHAR(10),
12>    salary      DECIMAL(10,2),
13>    start_Date  DATETIME,
14>    region      VARCHAR(10),
15>    city        VARCHAR(20),
16>    managerid   INTEGER
17> );
18> GO
1> INSERT INTO employee VALUES (1, 'Jason' ,  'Martin', 5890,'2005-03-22','North','Vancouver',3);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (2, 'Alison',  'Mathews',4789,'2003-07-21','South','Utown',4);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (3, 'James' ,  'Smith',  6678,'2001-12-01','North','Paris',5);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (4, 'Celia' ,  'Rice',   5567,'2006-03-03','South','London',6);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (5, 'Robert',  'Black',  4467,'2004-07-02','East','Newton',7);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (6, 'Linda' ,  'Green' , 6456,'2002-05-19','East','Calgary',8);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (7, 'David' ,  'Larry',  5345,'2008-03-18','West','New York',9);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (8, 'James' ,  'Cat',    4234,'2007-07-17','West','Regina',9);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (9, 'Joan'  ,  'Act',    6123,'2001-04-16','North','Toronto',10);
2> GO

(1 rows affected)
1>
2> select * from employee;
3> GO
id          first_name last_name  salary       start_Date              region     city                 managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
          1 Jason      Martin          5890.00 2005-03-22 00:00:00.000 North      Vancouver                      3
          2 Alison     Mathews         4789.00 2003-07-21 00:00:00.000 South      Utown                          4
          3 James      Smith           6678.00 2001-12-01 00:00:00.000 North      Paris                          5
          4 Celia      Rice            5567.00 2006-03-03 00:00:00.000 South      London                         6
          5 Robert     Black           4467.00 2004-07-02 00:00:00.000 East       Newton                         7
          6 Linda      Green           6456.00 2002-05-19 00:00:00.000 East       Calgary                        8
          7 David      Larry           5345.00 2008-03-18 00:00:00.000 West       New York                       9
          8 James      Cat             4234.00 2007-07-17 00:00:00.000 West       Regina                         9
          9 Joan       Act             6123.00 2001-04-16 00:00:00.000 North      Toronto                       10

(9 rows affected)
1>
2>
3> CREATE PROCEDURE spInsertOrUpdateEmployee
4> @FirstName nVarChar(50),
5> @LastName nVarChar(25),
6> @Salary Money
7> AS
8> IF EXISTS(SELECT * From Employee Where First_name = @FirstName)
9> UPDATE Employee SET Last_NAME = @LastName, Salary = @Salary
10> WHERE First_name = @FirstName
11> ELSE
12> INSERT INTO Employee (ID,First_Name, Last_Name, Salary)
13> SELECT 99, @FirstName, @LastName, @Salary
14> GO
1>
2>
3>
4>
5> drop table employee;
6> GO
1>








20.7.IF
20.7.1.The syntax of the IF...ELSE statement
20.7.2.Using an Expression with an Explicit Unknown Value
20.7.3.Using an Expression with an Unknown Value Returned from One of the Participating Simple Logical Expressions
20.7.4.Short circuit aborts any further processing of a logical expression as soon as its result can be determined.
20.7.5.IF (@au_id IS NULL)
20.7.6.IF EXISTS
20.7.7.Use function returned value
20.7.8.IF (SELECT ID FROM inserted) like '99[0-9][0-9]'
20.7.9.IF (SELECT COUNT(*) FROM inserted) > 1
20.7.10.If statement with aggregate function
20.7.11.Use if and like to check a pattern
20.7.12.Implementing the ELSE Statement In Our Sproc
20.7.13.A script that tests for outstanding Billings with an IF statement
20.7.14.uses an IF...ELSE statement