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What happens if a delete command is run on a table without a WHERE clause?
If you will not provide where clause with delete statement, then whole table data will be deleted. In the syntax above the deletion happens without any condition and will delete all the records of the table.
How do I find Top 5 records in SQL?
SQL SELECT TOP Clause
- SQL Server / MS Access Syntax. SELECT TOP number|percent column_name(s) FROM table_name;
- MySQL Syntax. SELECT column_name(s) FROM table_name. LIMIT number;
- Example. SELECT * FROM Persons. LIMIT 5;
- Oracle Syntax. SELECT column_name(s) FROM table_name. WHERE ROWNUM <= number;
- Example. SELECT * FROM Persons.
How to find details of customers who ordered?
Please note that I have seen a similar query here, but think my query is different enough to merit a separate question. Now suppose I would like to find the names of all the customers who have ordered more than 10 different types of product, and the number of types of products they ordered.
How to find total number of orders placed by customer?
SELECT customername, firstname, lastname, COUNT (DISTINCT (customernum)) FROM customer, orders, rep WHERE customer.customernum=orders.customernum ANDcustomer.repnum=rep.repnum AND customer.customernum=customernum; The code above gives me an error message “#1052 – Column ‘customernum’ in field list is ambiguous”.
Which is customer has placed most orders in Oracle?
For that, you have to tell what DBMS you use, since it varies with the DBMS the way you limit the query to the first one (ex: mysql is LIMIT 1, sql-server is TOP 1): This solution is for MySQL, as I have used LIMIT. It can be changed as per the DBMS.
How to get all customers with no orders?
The result of a left join always contains all records of the “left” table (Persons), even if the join-condition does not find any matching record in the “right” table (Orders). When there is no match, the columns of the “right” table will NULL in the result set. This should work… theres more than one way to do it.