Sql-Keywords (distinct , order by) and where clause

 Sql-Keywords (distinct , order by) and where clause

Distinct Keyword

The DISTINCT keyword is used to return only distinct (unique) column values.

Sql tables often contains many duplicate values in columns and sometimes you only want to list the unique(distinct) values.

sample table :

In table we can multiple name with same values.

to view on distinct column value following distinct command to execute

Select distinct empname from k4coding_emp

Distinct Keyword:

The ORDER BY keyword is used to sort the  output  in ascending or descending order.

ORDER BY Syntax

SELECT col1, col2,col3, ...

FROM tablename

ORDER BY col1, col2, ... ASC|DESC;

The ORDER BY keyword sorts the records in ascending order by default. 

Select * from k4coding_emp order by empname

To sort the records in descending order, use the DESC keyword.

Select * from k4coding_emp order by empname desc

Where Clause:

The SQL WHERE clause is used to filter the records, it contains logical conditions .

The WHERE clause is used to extract only those records that fulfill a specified condition.

WHERE clause  Syntax

SELECT col1, col2, ...

FROM table_name

WHERE condition;

Select * from k4coding_emp

where dept ='HR'