Bi-sql distinct

DISTINCT function

stay SQL in ,DISTINCT Function is also one of the common functions , It can usually be used to de duplicate tables or columns .

Its purpose and PowerBI-DAX Function DISTINCT Functions are similar , You can de duplicate tables or columns .

Basic grammar

grammar 1：

SELECT DISTINCT  Column name  FROM  The name of the table 

grammar 2：

SELECT DISTINCT * FROM  The name of the table 

notes ： Usually ,SQL Data warehouse is very strict for data storage , Each row of data has a corresponding primary key （ The unique identifier ）,DISTINCT It mainly solves the problems similar to the extraction of unique information .

Using examples

Case data 1：

In the native database of white tea , There is a name “TEST” The database of , Its name is “Distinct” Analog data sheet for , My friends can clearly see A01 The data in this row is repeated .

Example 1：

Import the entire table to PowerBI in .

SELECT 
      DISTINCT
      * 
      FROM 
      [Distinct]

give the result as follows ：

about A01 The repeated projects of are successfully removed , Redundant lines are removed .

Case data 2：

In the native database of white tea , There is a name “TEST” The database of , Its name is “ Sales details ” Analog data sheet for .

Example 2：

Re import the branch to PowerBI in .

SELECT
      DISTINCT
       The branch where you are 
      FROM
       Sales details 

give the result as follows ：

Successful de duplication of the branch column .

Example 3：

Re import the product name and the branch combination to PowerBI in .

SELECT
      DISTINCT
       Name of commodity ,
       The branch where you are 
      FROM
       Sales details 

give the result as follows ：

This is white tea , One PowerBI Beginners .