SQL Query Language Group By

sele date,a.win, b, lose from table, (sele date count(result) as win from table where rsult='Win'group by date )a,,(sele date count(result) as pay from table where rsult='Pay'group by date )b where table. date=table.

date= group by date

In SQL queries, the meaning of group by is to group data according to specified rules, and its function is to group query results according to the values of a column or multiple columns, and the values are equal to a group, and the group by statement is generally used with aggregate functions.

group by and order by

select category, sum(quantity) as sum of quantities from a group by category order by sum(quantity) desc

You can't use "Order by Sum of Quantities desc" in Access, but you can use it in SQL Server.

The field limit specified in the select section of group by.

select category, sum(quantity) as sum of quantities, summary from a group by category order by category desc

After the execution, an error message will be displayed, as shown in the following figure. This is the point to be aware that the fields specified in select should either be included after the group by statement as the basis for grouping; Either that or it should be included in the aggregate function.

group by all

select Category, Summary, sum(quantity) as sum of quantities from a group by all Category, Summary.

you can specify a Summary field because the Multi-Column Grouping contains a Summary Field, and the result is as follows.

In example 4, you can see that "a, a2001, 13" is the merge of "a, a2001, 11" and "a, a2001, 2".

Although "Group by All" is supported in SQL Server, Group by All will be removed in future versions of Microsoft SQL Server to avoid use in new development work, and "Group by All" is not supported in Group By, but Multi-column grouping is also supported in Access, and the SQL in the above SQL Server can be written in Access.

select Category, Summary, sum(quantity) as sum of quantities from a group by Category, Abstract.

Group queries.

The groupby statement literally means "grouping according to certain rules". Its function is to divide a dataset into several small regions through certain rules, and then process data for several small regions.

2.Use of group by:

The understanding of the group by statement has been given above. Based on this understanding and the SQL Server 2000 online help, the following is a list of typical uses of the Group By statement.

group by [expressions]:

This is probably the most common use of the group by statement, group by + group field] (there can be more than one). After this is done, the dataset divides a dataset into different groups based on the values of the grouping fields. For example, in the following dataset, the fruitname and the country of origin are the joint primary keys:

1. The groupby statement in the SQL statement is: the group by statement is used to group the result set according to one or more columns in combination with the total function.

2. High-level syntax of SQL statement group by:

1. Write an SQL statement to create a table. Of course, we can also create with blueprints;

2. select * from student, we enter a query statement to show all the data we just inserted;

3、select stuname,count(*)from student group by stuname。From the above results, it is not difficult to see that we have grouped students according to their names, and another way to say this is to filter the duplicates, group the names in the student table by group, and use the aggregate function (count) to count the number of occurrences of each name.

There are many skills in SQL statements, and there are many others in addition to the addition, deletion, modification and query when we first learned. When installing, you must also remember to see how many bits your operating system is. If you are a 32-bit operating system, you can install any 32-bit version of SQLServ.