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Found 6705 Articles for Database

152 Views
For calculating the sum of only dissimilar values of the column we can use ‘DISTINCT’ keyword along with the name of the column. To understand SUM() function for dissimilar values, consider an ‘employee_tbl’ table, which is having the following records −mysql> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | 2007-05-27 | 220 | | 3 | Jack | 2007-05-06 | 170 ... Read More

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With the help of SHOW TABLES command, we can get only the name having no other information about the tables. For example, we can see the list of tables in a database named tutorial as follows −mysql> show tables; +--------------------+ | Tables_in_tutorial | +--------------------+ | student | +--------------------+ 1 row in set (0.00 sec)

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When we use MySQL COUNT() function to count the values stored in a column which also stored some NULL values then MySQL ignores the NULL and returns the result for only non-NULL values. To understand it, we are using the data, as follows, from table ‘Employee’ −mysql> Select * from Employee; +----+--------+--------+ | ID | Name | Salary | +----+--------+--------+ | 1 | Gaurav | 50000 | | 2 | Rahul | 20000 | | 3 | Advik | 25000 | | 4 | Aarav | 65000 | | 5 | Ram | 20000 | | 6 | ... Read More

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MySQL ADDTIME() function can be used to add a time interval in the data stored in a column of the table. The syntax of this function is ADDTIME(date, ‘expression unit’). It can be demonstrated by following the example which uses the data from table ‘collegedetail’. mysql> Select estb, ADDTIME(estb, '05:04:25')AS 'Date with time' From collegedetail WHERE ID = 111; +------------+---------------------+ | estb | Date with time | +------------+---------------------+ | 2010-05-01 | 2010-05-01 05:04:25 | +------------+---------------------+ 1 row in set (0.02 sec) Here, ‘estb’ is a column of table ‘collegedetail’ having the date as values.

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Two functions can be used for this purpose and in both the functions we need to provide column name as an argument along with INTERVAL keyword. The functions are as follows −DATE_ADD() functionThe syntax of this function is DATE_ADD(date, INTERVAL expression unit). It can be demonstrated by following the example which uses the data from table ‘collegedetail’ −mysql> Select estb, DATE_ADD(estb, INTERVAL 10 DAY) from collegedetail; +------------+---------------------------------+ | estb | DATE_ADD(estb, INTERVAL 10 DAY) | +------------+---------------------------------+ | 2010-05-01 | 2010-05-11 | | 1995-10-25 | 1995-11-04 ... Read More

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We can check the status of tables in a database with the help of show table status statement. For example, in the database named tutorial, by executing this statement we can get the status of tables as follows −mysql> show table status \G*************************** 1. row *************************** Name: student Engine: InnoDB Version: 10 Row_format: Compact Rows: 0 Avg_row_length: 0 Data_length: 16384 Max_data_length: 0 Index_length: 0 Data_free: 7340032 Auto_increment: NULL Create_time: 2017-10-24 09:34:29 ... Read More

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By using –v option in batch mode, the MySQL statements can be printed along with output. For example, after running the same query in batch mode with –v option we will get the statement printed along with output.C:\Program Files\MySQL\bin>mysql -u root -p gaurav < hh.sql -v Enter password: ***** -------------- select * from hh -------------- id 1 2It is showing the statement select * from hh which is written in the file hh.sql.

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We can get the MySQL output format in batch mode with the help of –t option. For example, after running the same query in batch mode with –t option we will get the output like interactive format.ExampleC:\Program Files\MySQL\bin>mysql -u root -p gaurav < hh.sql -t Enter password: *****Output+------+ | id | +------+ | 1 | | 2 | +------+

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The default MySQL output would be different if we will run the same query interactively or in batch mode. For example, if we will run the query select * from hh interactively then following would be a format of output −mysql> select * from hh; +------+ | id | +------+ | 1 | | 2 | +------+ 2 rows in set (0.01 sec)On the other hand, if we will run the same query in batch mode then following would be the format of output −C:\Program Files\MySQL\bin>mysql -u root -p gaurav < hh.sql Enter password: ***** id 1 2

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We need to create a .sql file for running MySQL in batch mode. This file will contain the MySQL statements. Suppose I have hh.sql file in which I have written the statement select * from hh. With the help of the following command, we can run this file in batch mode −ExampleC:\Program Files\MySQL\bin>mysql -u root -p gaurav < hh.sql Enter password: *****Outputid 1 2Here Gaurav is the database name that contains the table hh. Whenever you’ll run this command it will ask for the password and then give the output.