SELECT Statement in SQL
The Select statement in SQL is the most commonly query-used statement in SQL. It is used to either fetch data according to some specified rule or display an entire table in SQL. The data displayed after the query execution is stored in a result table.
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In this tutorial section, we will discuss on:
A Brief on the SELECT Query in SQL
The Select query in SQL is one of the most important commands in SQL, and it is used to get data from a table.
Syntax
SELECT column1, column2, columnN
FROM tablename;
where SELECT and FROM are the keywords; column1 to columnN are a set of columns, and tablename is the name of the table followed by a semicolon.
How to Select Data from a Table?
- Let’s display the name and age of an employee from the employee table
Select e_name From employee; (single column)
Select e_name, e_age From employee;
- After writing the query, click on the execute button to check for errors
- Once the query is executed, the table appears
The Select option contains the table name and the From option contains the table name from where we want to fetch the data.
- To select everything from a table, use * (asterisk operator)
Select * from employee;
- After writing the query, click on the execute button to check for errors
- Once the query is executed, the table appears
Select Distinct in SQL
A column often contains many duplicate values, and sometimes the information needed from a single column has to be distinct. Using the SELECT DISTINCT statement in SQL, we can filter out distinct values from a column.
Syntax
SELECT DISTINCT column1, column2, columnN
FROM tablename;
where SELECT DISTINCT and FROM are the keywords, column1 to columnN are a set of columns, and tablename is the name of the table, followed by a semicolon.
How to Select Distinct Data from a Table?
- Let’s select some distinct values from our employee table. If we have a glance at the gender column, we can see that two values are being repeated, male and female.
select distinct e_gender from employee;
- After writing the query, click on the execute button to check for errors
- Once the query is executed, the table appears
Let’s remove the distinct keyword and run the query.
select e_gender from employee;
- After writing the query, click on the execute button to check for errors
- Once the query is executed, the table appears
When the distinct keyword was removed, all values got displayed., which gives us a clear picture of the Select Distinct statement; it gets only the values which are different.
This bring us to the end of this Select Query in SQL. Here, we learned to use Select Command in SQL and Select Distinct command in SQL .