How can a table be deleted from the database? provide an example.
Data management can be a challenge given the massive amounts of data to deal with. Anyone who manages data knows that sometimes, we need to delete some data from our database, due to changes in the real-world. For example, when a store stops selling an item, its record is removed from the inventory database.
This is done with the help of the SQL Delete command. This command is a significant and integral part of this query language. The Delete command in SQL is a part of the Data Manipulation Language, a sub-language of SQL that allows modification of data in databases. This command is used to delete existing
records from a table. Using this, you can either delete specific records based on a condition or all the records from a table. NOTE: It is crucial to be entirely sure about using this command, as it deletes the data permanently. To start using the Delete command, we need to know its syntax. DELETE FROM table_name WHERE [condition]; NOTE: Extra caution needs to be taken with the WHERE clause as, without it,
all the rows from the table will get deleted. Multiple conditions can be specified in the WHERE clause with the help of AND and OR operators. Let’s apply the concepts stated above to the rows of a table. Let’s take a sample “Employee_details” table; As we can see, one record has been deleted based on the condition specified in the WHERE clause.
As we can see, “Name” is of character string data type, so the value being specified has to be enclosed in single inverted commas, without which the system will return a syntax error. The query above will result in the following:
From the table displayed above, we need to delete all the employee records with salary less than 60000: This will result in the following: As we can see, four rows have been deleted. More than one condition can be applied to the columns using a single query. Let’s see how that is done. Deleting Specific Rows Based on Multiple ConditionsWe can use AND and OR operators to combine multiple conditions in the WHERE clause of a DELETE command.
From our sample “Employee_details” table, to delete all employee records where the employee name is “Ajay” or the city is “Chennai”:
This will result in the following:
As we can see, both the rows satisfying either of the conditions have been deleted.
From the above table, we need to delete all the records for employees that belong to “Bangalore” and have a salary less than 50000: This will result in the following: As we can see, only the one record that satisfies both the conditions has been deleted. Let’s see what happens when we don’t use the WHERE clause. Deleting All the Records From a TableIt’s imperative to be extremely careful while using the DELETE command on a table as the data gets deleted permanently.
To delete all the records from our “Employee_details” table, we’ll use the following query: To check whether all the records are deleted, we’ll use the SELECT command: As we can see, the SELECT command returns an empty set as all the records from the “Employee_details” table have been deleted.
This is a part of the Data Definition Language, a sub-language of SQL that allows the creation and modification of database objects. The syntax of this command is: As we can see, there is no ‘WHERE’ clause, so this command is used only when we need to empty the contents of a table. To delete all the records from the “Employee_details” table: To check whether all the records have been deleted: As we can see, the records have been deleted and the table returns an empty set. Gain expertise in the latest Business analytics tools and techniques with the Business Analyst Master's Program. Enroll now! Next StepsDeleting records from tables and databases is a huge part of managing data. Sometimes, we insert the wrong data, or the data in a table becomes outdated and needs modification, all of this requires the help of Delete in SQL. Check out our tutorials to learn how to delete duplicate rows in tables and many SQL statements. Now that you know how to delete existing records, it is time for you to start learning about other SQL commands so that you can start manipulating and querying data and move forward in your journey to become an expert in SQL. If you liked this article, you must check out our Business Analyst Master’s Program as it covers the A-Z of SQL as well. Do you have any questions for us? Mention them in the comment section of our “Delete in SQL” article, and we’ll have our experts in the field answer them for you. How do you delete a table from a database?To delete a table from the database. In Object Explorer, select the table you want to delete.. Right-click the table and choose Delete from the shortcut menu.. A message box prompts you to confirm the deletion. Click Yes. Note. Deleting a table automatically removes any relationships to it.. How do you delete and delete a table in SQL?SQL DELETE Statement. DELETE FROM table_name WHERE condition;. Example. DELETE FROM Customers WHERE CustomerName='Alfreds Futterkiste';. DELETE FROM table_name;. Example. DELETE FROM Customers;. Which command deletes a table in the database?We use the SQL DROP Table command to drop a table from the database. It completely removes the table structure and associated indexes, statistics, permissions, triggers and constraints.
How do I delete a table in MySQL?To permanently remove a table, enter the following statement within the MySQL shell: DROP TABLE table1; Replace table1 with the name of the table you want to delete. The output confirms that the table has been removed.
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