Subqueries: calculate an aggregate value on the fly and use it in the outer query for comparison : Sub query « Table « SQL Server / T-SQL

SQL Server / T-SQL
1. Aggregate Functions
2. Analytical Functions
3. Constraints
4. Cursor
5. Data Set
6. Data Type
7. Database
8. Date Timezone
9. Index
10. Insert Delete Update
11. Math Functions
12. Select Query
13. Sequence
14. Store Procedure Function
15. String Functions
16. Subquery
17. System
18. Table
19. Table Joins
20. Transact SQL
21. Transaction
22. Trigger
23. View
24. XML
Java
Java Tutorial
Java Source Code / Java Documentation
Java Open Source
Jar File Download
Java Articles
Java Products
Java by API
C# / C Sharp
C# / CSharp Tutorial
ASP.Net
JavaScript DHTML
JavaScript Tutorial
JavaScript Reference
HTML / CSS
HTML CSS Reference
C / ANSI-C
C Tutorial
C++
C++ Tutorial
PHP
Python
SQL Server / T-SQL Tutorial
Oracle PL / SQL
Oracle PL/SQL Tutorial
PostgreSQL
SQL / MySQL
MySQL Tutorial
VB.Net
VB.Net Tutorial
Flash / Flex / ActionScript
VBA / Excel / Access / Word
Microsoft Office PowerPoint 2007 Tutorial
Microsoft Office Excel 2007 Tutorial
Microsoft Office Word 2007 Tutorial
SQL Server / T-SQL » Table » Sub query 
Subqueries: calculate an aggregate value on the fly and use it in the outer query for comparison


1>
2CREATE TABLE works_on        (emp_no       INTEGER NOT NULL,
3>                         project_no    CHAR(4NOT NULL,
4>                         job CHAR (15NULL,
5>                         enter_date    DATETIME NULL)
6>
7insert into works_on values (1'p1', 'analyst', '1997.10.1')
8insert into works_on values (1'p3', 'manager', '1999.1.1')
9insert into works_on values (2'p2', 'clerk',   '1998.2.15')
10insert into works_on values (2'p2',  NULL,     '1998.6.1')
11insert into works_on values (3'p2',  NULL,     '1997.12.15')
12insert into works_on values (4'p3', 'analyst', '1998.10.15')
13insert into works_on values (5'p1', 'manager', '1998.4.15')
14insert into works_on values (6'p1',  NULL,     '1998.8.1')
15insert into works_on values (7'p2', 'clerk',   '1999.2.1')
16insert into works_on values (8'p3', 'clerk',   '1997.11.15')
17insert into works_on values (7'p1', 'clerk',   '1998.1.4')
18>
19select from works_on
20> GO

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)
emp_no      project_no job             enter_date
----------- ---------- --------------- -----------------------
          p1         analyst         1997-10-01 00:00:00.000
          p3         manager         1999-01-01 00:00:00.000
          p2         clerk           1998-02-15 00:00:00.000
          p2         NULL            1998-06-01 00:00:00.000
          p2         NULL            1997-12-15 00:00:00.000
          p3         analyst         1998-10-15 00:00:00.000
          p1         manager         1998-04-15 00:00:00.000
          p1         NULL            1998-08-01 00:00:00.000
          p2         clerk           1999-02-01 00:00:00.000
          p3         clerk           1997-11-15 00:00:00.000
          p1         clerk           1998-01-04 00:00:00.000

(11 rows affected)
1> -- Subquery Advantages
2>
3> -- Subqueries: calculate an aggregate value on the fly and use it in the outer query for comparison.
4>
5SELECT emp_no, enter_date FROM works_on
6>         WHERE enter_date = (SELECT min(enter_dateFROM works_on)
7> GO
emp_no      enter_date
----------- -----------------------
          1 1997-10-01 00:00:00.000

(rows affected)
1>
2> drop table works_on
3> GO
1>
2>
           
       
Related examples in the same category
1. Use aggregate function in sub-query
www.java2java.com | Contact Us
Copyright 2010 - 2030 Java Source and Support. All rights reserved.
All other trademarks are property of their respective owners.