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SQL database which aggregation operators, many novices are not very clear, in order to help you solve this problem, the following editor will explain for you in detail, people with this need can come to learn, I hope you can gain something.

Introduction to aggregation in the SQL database: aggregation values in a column is another type of operation that treats relationships as a whole. Aggregation refers to the operation of forming a single value from a series of values that appear in a column. For example, the sum or average of the values in a column. In SQL, we can not only aggregate by column, but also group tuples in a relationship according to certain conditions, such as values in another column, and then aggregate by group.

Common aggregation operators

SQL provides five operators suitable for columns in a relationship that can produce summary or aggregate information for that column. These operators are:

1. SUM, the sum of the values in the column

2. AVG, the average of each value in the column

3. MIN, the minimum value in this column

4. MAX, the value in this column

5. COUNT, the number of values (including copies if they are not explicitly deleted with DISTINCT).

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