The syntax for writing DROP command to delete a database in SQL is as follows : The basic syntax for writing DROP command to delete a database in SQL is as follows : We cannot perform a rollback operation to undo a DROP database/table command. We can even delete the database using the DROP command. DROPĭROP TABLE SQL command is used to delete a database object from the database. So what do we observe? We observe that the TRUNCATE command erases all the data from the table but maintains the table structure. Let us check it using the following SELECT statement. We have successfully removed all the records from the database.

Now let us have a look at an example illustrating TRUNCATE command. The generic syntax used for writing TRUNCATE command is as follows : Ergo, we cannot perform a rollback operation to undo a TRUNCATE command. TRUNCATE TABLE command is used to remove all the data records from the database table. Here is an example to remove an existing column from a database table. The syntax used for altering a table in SQL by deleting existing columns is as follows : Here is an example to rename an existing database table. The syntax used for renaming a table is as follows: Here is an example to add a new column to an existing table.ĪDD email_address character varying(255) The syntax used for altering a table in SQL by adding a new column is as follows : It can further be used to add and remove various constraints on an existing database table. Location character varying(255) NOT NULL,ĪLTER command in SQL is used to add, rename or modify, drop/delete columns in an existing database table. Here is an example to illustrate database table creation using the CREATE command.Ĭustomer_name character varying(255) NOT NULL, The basic syntax for creating a table in SQL is as follows:Ĭolumn_name_1 datatype ,Ĭolumn_name_2 datatype , But for that, we first need to know the syntax. Here is an example to illustrate database creation in SQL. The syntax for creating a database is as follows : CREATEĬREATE is a data definition language(DDL) command that is used for creating database objects such as database and database table. Now we will try to understand each of the above mentioned DDL commands in great detail in the subsequent sections. Used to write comments within SQL queries. Used to remove all the records from a database table. Used for removing an entire database or a database table. Used for modifying and renaming elements of an existing database table. Used for creating database objects like a database and a database table. Hadoop, Data Science, Statistics & others Command

Sql database commands list