SQL Tutorial: SQL SELECT DISTINCT Instance Tutorial

SQL Tutorial: SQL SELECT DISTINCT Instance Tutorial

This chapter will explain the choice of discrete speakers.


Select a different declaration in SQL
In one table, some columns may contain duplicate values. This is not a problem, however, sometimes you will want to list only the different (different) values on the table.

Unique keywords can be used to return only unique (different) values.

SQL SELECT DISTINCT syntax.

SELECT DISTINCT column_name (s) from
table_name

Let's take a look at an example of a distinct record.

 
   
   
 
    
    
 
     
 
      
_id  
 
      
lastname 
 
      
firstname 
 
      
address 
 
      
city 
 
     
 
     
 
      
 1 
 
      
 Hansen 
 
      
 ola 
 
      
 timoteivn 
 
      
 S Andnes 
 
     
 
     
 
      
 2 
 
      
 svendson 
 
      
 Tove 
 
      
 borgvn 
 
      
 Sandnes 
 
     
 
     
 
      
 3 
 
      
 Pettersen 
 
      
 Kari 
 
      
 storgt 
 
      
 stavanger 
 
     
 
    
 
   
   
 

 
   
   
 
    
    
 Now we want to select only the different values from the column named "City" from the above table. 
 
 We use the following SELECT statement: 
 
    
    
 select DISTINCT City from Persons 
 
    
    
   
 
    
    
 The results are as follows. 
 
    
    
 
     
     
 
      
      
 
       
 
        
city 
 
       
 
       
 
        
 sandnes 
 
       
 
       
 
        
 Stavanger