.
When multiple group by columns exist, ROLLUP produces more complex results. At this time, each time a "break" appears in any column except the last classification column (value change), the inquiry will generate a high clustering cumulative row.
For example, in the absence of ROLLUP, a yearly, country, and product-based sales table list may be as follows:
01mysql> SELECT year, country, product, SUM(profit)02 -> FROM sales03 -> GROUP BY year, country, product;04+------+---------+----
://research.microsoft.com/en-us/groups/mlp/default.aspx(20) Research and study Forum; http://bbs.matwav.com/(21) Liuqingshan, assistant professor, Rutgers University, USA; http://www.research.rutgers.edu/~qsliu/(22) The latest information network of computer vision; http://www.cvchina.info/(23) test video download for motion detection, shadowing and tracking; http://apps.hi.baidu.com/share/detail/18903287(24) Prof. Xiaogang Wang, assistant professor o
, and product may be as follows:
Mysql> SELECT Year, country, product, SUM (profit)
-> from sales
-> GROUP by year, country, product;
+------+---------+------------+-------------+
| Year | Country | Product | SUM (Profit) |
+------+---------+------------+-------------+
| 2000 | Finland | Computer | 1500 |
| 2000 | Finland | Phone | 100 |
| 2000 | India | Calculator | 150 |
| 2000 | India | Computer | 1200 |
| 2000 | USA | Calcula
Vend_country. In addition, you need to enclose the vend_country in parentheses.In the SELECT statement in SQL, you can use a special operator to stitch together two columns.Depending on the DBMS you are using, this operator can be used with a plus (+) or two vertical bar (| | ) indicatesDescription: + with | |Access and SQL Sever use the + sign. Db2,orcale,postgresql,sqlite and open Office Base using | |Liezi:SELECT vend_name+_ ' (' +vend_country+ ') 'From vendorsORDER by Vend_name;Output:(No c
column (value change), the inquiry will generate a high clustering cumulative row.
For example, in the absence of ROLLUP, a yearly, country, and product-based sales table list may be as follows:
mysql> SELECT year, country, product, SUM(profit) -> FROM sales -> GROUP BY year, country, product;+------+---------+------------+-------------+| year | country | product | SUM(profit) |+------+---------+------------+-------------+| 2000 | Finland | Computer | 1500 || 2000 | Finla
USA Tom M 1970-09-02 USAUse the following command to load the text file "Mytable.txt" into the mytable table: mysql> load DATA LOCAL INFILE "Mytable.txt" intotable pet;Then use the following command to see if the data has been entered into the database table: mysql> select * FROM MyTable;In this article we learned how to create a database and database table and how to add records to a database table. So how do we retrieve data from a database table?1
whether the data has been input to the database table:Mysql> select * from mytable;In the previous article, we learned how to create a database and a database table, and how to add records to a database table.How can we retrieve data from database tables?1. Retrieve Information from a database tableIn fact, we have used the Select statement to retrieve information from database tables.The select statement format is generally:Select search keyword FROM the retrieved table Where search condition
://research.microsoft.com/en-us/groups/vc/(19) Shine ML and CV Study Group; http://research.microsoft.com/en-us/groups/mlp/default.aspx(20) Research and study Forum; http://bbs.matwav.com/(21) Liuqingshan, assistant professor, Rutgers University, USA; http://www.research.rutgers.edu/~qsliu/(22) The latest information network of computer vision; http://www.cvchina.info/(23) test video download for motion detection, shadowing and tracking; http://apps.h
. How to load delimitation data
1 data that is delimited by a particular character, may be enclosed in quotation marks, which is the most common data format for the current flat file.For bound data, the most commonly used format is comma-delimited value format. With this file format, each field in the data is separated by a comma from the next field. Text strings can be enclosed in quotes so that the string itself contains commas. If the string must also contain quotes, the general convention i
://research.microsoft.com/en-us/groups/vc/ (19) Shine ML and CV Study Group; http:// Research.microsoft.com/en-us/groups/mlp/default.aspx (20) Research and study Forum; http://bbs.matwav.com/(21) Liuqingshan, assistant professor, Rutgers University, USA; http://www.research.rutgers.edu/~qsliu/(22) The latest information network of computer vision; http://www.cvchina.info/(23) test video download for motion detection, shadowing and tracking; http://app
retrieved table Where the search condition (optional)The "*" used previously indicates that all columns are selected.The following continues with the table mytable we created in the previous article:2. Query all data:Mysql> select * FROM MyTable;+----------+------+------------+----------+| name | sex | Birth | birthaddr |+----------+------+------------+--------+| Abccs|f| 1977-07-07 | China || Mary |f| 1978-12-12 | USA || Tom |m| 1970-09-02 |
C ++: BjarneStroustrupPHP: RasmusLerdorfDelphiC #: andreshejlsberg C ++: Bjarne Stroustrup
PHP: Rasmus Lerdorf
Delphi/C #: Anders Hejlsberg reply: because there is a lot of bearded people, whether the language can be successful depends on the designer's beard.
I don't know whether young people have heard of this stalk.
By the way, although the author of ruby is a Japanese, he left a big beard and took a photo after hearing that he had no beard and ruby would inevitably fail.
I have more beard
(Click the public number above for a quick follow-up)
Turn from: The forefront of technology (TOPITNEWS)
If you have a good article to submit, please click here to learn more
Yahoo News October 24 issued a report, said the United States news and World Report released the 2018 global university rankings of the latest. Take us to focus on the rankings of the computer (computer science) majors.
To add, U.S. News World Reports is the third-largest news magazine in the United States, second only
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.