how to find unique values in sql code example

Example 1: distincct sql

SELECT DISTINCT column1, column2, ...

 FROM table_name;

Example 2: how to select unique element in sql

DISTINCT
- select distinct * from employees; ==> 
  retrieves any row if it has at
  least a single unique column.

- select distinct first_name from employees; ==> 
      retrieves unique names
     from table. (removes duplicates)
     
- select distinct count(*) from employees;
     retrieve number of unique rows
     if any row has at least a single unique data.

Example 3: how to find unique element in sql

DISTINCT
- select distinct * from employees; ==> 
           retrieves any row if it has at 
           least a single unique column.
- select distinct first_name from employees; ==> 
              retrieves unique names
              from table. (removes duplicates)
- select distinct count(*) from employees;
          retrieve number of unique rows
          if any row has at least a single unique data.

Example 4: sql find all different values in column

SELECT DISTINCT
    column_name
FROM
    table_name;

Example 5: unique key in sql

Unique Key:
Only unique value and also can contain NULL

Example 6: sql distinct

#List unique values in the df['name'] column
df.name.unique()