With the help of following MySQL command, we can check the tables of a database other than the database we are currently using −Show Tables from Database_name;For example, the following query would display the list of tables from a database named ‘gaurav’ when currently we are using a database named ‘new’ −mysql> use new; Database changed mysql> show tables from gaurav; +--------------------+ | Tables_in_tutorial | +--------------------+ | testing            | | employee           | | tender             | | Ratelist           | +--------------------+ 4 rows in set (0.00 sec)

For getting the records from MySQL table in the result set in a particular way either ascending or descending, we need to use the ORDER BY clause along with ASC or DESC keywords. If we will not use any of the above-mentioned keywords then MySQL by default return the records in ascending order. The ORDER BY clause returned the result set based on a particular field (ascending or descending order) with which we will use the ORDER BY clause. Suppose we want to sort the rows of the following table −mysql> Select * from Student; +--------+--------+--------+ | Name   | ... Read More

By using the WHERE clause with a DISTINCT clause in MySQL queries, we are putting a condition on the basis of which MySQL returns the unique rows of the result set. By using the LIMIT clause with a DISTINCT clause in MySQL queries, we are actually providing a perimeter to the server about a maximum number of unique rows of the result set to be returned.ExampleWe can use WHERE and LIMIT clause with DISTINCT as follows on the table named ‘testing’ −mysql> Select * from testing; +------+---------+---------+ | id   | fname   | Lname   | +------+---------+---------+ |  200 ... Read More

As we know that in trigger definition, we can refer to columns of the row being inserted, updated or deleted. Following are the ways OLD and NEW keywords enable us to access columns − We must have to prefix the column name with a qualifier of OLD to refer to a value from the original row. We must have to prefix the column name with a qualifier of NEW to refer to a value in the new row. Now, the use of OLD and NEW must be done appropriately because the triggering event Determines which of them are ... Read More

Yes, it is possible to use MySQL GROUP BY clause with multiple columns just as we can use MySQL DISTINCT clause. Consider the following example in which we have used DISTINCT clause in first query and GROUP BY clause in the second query, on ‘fname’ and ‘Lname’ columns of the table named ‘testing’.mysql> Select * from testing; +------+---------+---------+ | id   | fname   | Lname   | +------+---------+---------+ |  200 | Raman   | Kumar   | |  201 | Sahil   | Bhalla  | |  202 | Gaurav  | NULL    | |  203 | Aarav   | ... Read More

When we use the GROUP BY clause in the SELECT statement without using aggregate functions then it would behave like the DISTINCT clause. For example, we have the following table −mysql> Select * from testing; +------+---------+---------+ | id   | fname   | Lname   | +------+---------+---------+ |  200 | Raman   | Kumar   | |  201 | Sahil   | Bhalla  | |  202 | Gaurav  | NULL    | |  203 | Aarav   | NULL    | |  204 | Harshit | Khurana | |  205 | Rahul   | NULL    | |  206 | ... Read More

We can use the DISTINCT clause on more than columns in MySQL. In this case, the uniqueness of rows in the result set would depend on the combination of all columns.ExampleConsider the following table ‘testing’ having 10 rows −mysql> select * from testing; +------+---------+---------+ | id   | fname   | Lname   | +------+---------+---------+ |  200 | Raman   | Kumar   | |  201 | Sahil   | Bhalla  | |  202 | Gaurav  | NULL    | |  203 | Aarav   | NULL    | |  204 | Harshit | Khurana | |  205 | Rahul ... Read More

We can destroy a trigger in two ways −Dropping a trigger explicitlyWith the help of the DROP statement, we can destroy a trigger explicitly. It can be understood with the help of the following example −mysql> DROP Trigger before_inser_studentage1; Query OK, 0 rows affected (0.05 sec)Dropping a trigger implicitlyA trigger will be destroyed implicitly if the table with which it is associated is destroyed or if the database which it is associated is destroyed.

While querying data from a MySQL table, we may get duplicate values from a column. With the help of the DISTINCT clause in the SELECT statement, we can get rid of duplicate data in the result set.SyntaxSELECT DISTINCT Columns FROM Table_name WHERE conditions;ExampleFor example, we have a table named ‘tender’ having the following columns −mysql> Select * from tender; +----------+--------------+--------------+-------+ | clientid | client_Fname | Client_Lname | value | +----------+--------------+--------------+-------+ |      100 | Mohan        | Kumar        | 60000 | |      101 | Sohan        | Singh     ... Read More

By using DISTINCT keyword along with column name as the argument of COUNT() function we can count the number of unique values in a column. The syntax is as follows − SELECT COUNT(DISTINCT Col_name) FROM table_name; Example Suppose we have the following table mysql> Select * from tender; +----------+--------------+--------------+-------+ | clientid | client_Fname | Client_Lname | value | +----------+--------------+--------------+-------+ | 100 | Mohan | Kumar | 60000 | | 101 | Sohan ... Read More