Acoustica 7 union keyword how to#

Now we will use DML statements to enter data in the table. This will create a table having four columns customer_id, name, city, and state. LetвЂ™s create a table CUSTOMER using DDL statements(data definition language) and then populate them using DML( Data manipulation language).Д¬REATE TABLE customer ( customer_id int NOT NULL, name char(50) NOT NULL, city varchar2, state varchar2) LetвЂ™s now learn where to use distinct keyword with the help of examples.

Acoustica 7 union keyword how to#

How to Use Distinct Keyword in SQL?ДЄs we have already discussed the parameters.

So if we have null values, then the result set for a distinct keyword will also include a null value. Note:В In SQL, a distinct keyword also retrieves the null value, which means it considers null also as a distinct value.

Conditions: This is purely optional we provide conditions when we want the data to first satisfy a particular condition for the records to get selected.

One thing to note is that there should be at least one table name after from clause.

Tables: We provide the table names from which we want the records.

Expressions: In this, we provide the column names or calculations that we want.

Select DISTINCT(expressions) from tables Below is the syntax for a distinct keyword. LetвЂ™s now look at the various parameters present in a distinct keyword. Parameters used for Distinct Keyword in SQL If we remove a distinct keyword, it will retrieve four values instead of three.

On running, it will return the unique city names, which are Mumbai, Delhi, Lucknow. In our example above, we can see that the city is the column that has repetitive values, so we will put the city in place of column_name and employee in place of table_name. Select DISTINCT(column_name) from table_name

LetвЂ™s have an employee table with three columns: empId, empname, and city, as shown below: LetвЂ™s look at the distinct keyword syntax with an example: Hadoop, Data Science, Statistics & others