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MySQLi Articles
Page 79 of 341
How can we update MySQL table after removing a particular string from the values of column?
We can update MySQL table after removing a particular string from the values of a column by using TRIM() function along with UPDATE clause. Following the example from ‘examination_btech’ table will make it clearer −ExampleSuppose if we want to delete the values ‘(CSE)’, from last, of column ‘Course’ and want to update the table too then it can be done with the help of the following query −mysql> Update examination_btech SET Course = TRIM(Trailing '(CSE)' FROM Course); Query OK, 10 rows affected (0.13 sec) mysql> Select * from examination_btech; +-----------+----------+--------+ | RollNo | Name | Course | +-----------+----------+--------+ | 201712001 | Rahul ...
Read MoreHow can I get the list of columns from a table in the other database than we are currently using?
It can be done with the SHOW COLUMNS statement. Its Syntax would be as follows −SyntaxSHOW COLUMNS FROM db_name.tab_nameHere, tab_name is the name of the table from which we want to see the list of columns.Db_name is the name of the database, in which the table is storedExampleIn the example we are currently using the database ‘query’ and getting the list of columns from table named ‘arena’ stored in mysql ‘database’ −mysql> SHOW COLUMNS FROM mysql.arena\G *************************** 1. row *************************** Field: id Type: int(10) unsigned zerofill Null: NO Key: PRI Default: NULL Extra: auto_increment ...
Read MoreHow can we set up a MySQL User account by using INSERT INTO statement?
For adding a new user to MySQL, we just need to add a new entry to the user table in the database mysql. To illustrate it we are using the following example −ExampleThe following program is an example of adding a new user guest with SELECT, INSERT and UPDATE privileges with the password guest123; the SQL query is −root@host# mysql -u root -p Enter password:******* mysql> use mysql; Database changed mysql> INSERT INTO user (host, user, password, select_priv, insert_priv, update_priv) VALUES ('localhost', 'guest', PASSWORD('guest123'), 'Y', 'Y’, 'Y'); Query OK, 1 row affected (0.20 sec) mysql> FLUSH PRIVILEGES; Query OK, ...
Read MoreHow can we set up a MySQL User account by using SQL GRANT statement?
We can also add user account by using GRANT SQL command. It can be illustrated by using the following example −ExampleIn this example, we will add user Zara with password zara123 for a particular database,which is named as TUTORIALS.root@host# mysql -u root -p password; Enter password:******* mysql> use mysql; Database changed mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP -> ON TUTORIALS.* -> TO 'zara'@'localhost' -> IDENTIFIED BY 'zara123';The above statements will also create an entry in the MySQL database table called as a user.
Read MoreHow can we use MySQL POWER() function with the column’s data values?
If we want to use POWER() function with column’s data values then the first argument i.e. the base would be the name of the column and the second argument i.e. the exponent would be as specified by us. To understand it considers a table ‘Employee’ having the following records −mysql> Select * from Employee; +----+--------+--------+ | ID | Name | Salary | +----+--------+--------+ | 1 | Gaurav | 50000 | | 2 | Rahul | 20000 | | 3 | Advik | 25000 | | 4 | Aarav | 65000 | | 5 | Ram | 20000 | ...
Read MoreHow can I get the list of columns from a table in the database we are currently using?
It can be done with the SHOW COLUMNS statement. Its Syntax would be as follows −SyntaxSHOW COLUMNS FROM tab_nameHere tab_name is the name of the table from which we want to see the list of columns.ExampleIn the example we are getting the list of columns from a table named Student_info −mysql> SHOW COLUMNS FROM Student_info\G *************************** 1. row *************************** Field: studentid Type: int(11) Null: YES Key: Default: NULL Extra: *************************** 2. row *************************** Field: Name Type: varchar(40) Null: YES Key: Default: NULL Extra: *************************** 3. row *************************** ...
Read MoreHow Can MySQL operator precedence affect result set?
MySQL follows operator precedence and it has the following list of operators, having the same precedence which is on the same line −INTERVAL BINARY, COLLATE ! - (unary minus), ~ (unary bit inversion) ^ *, /, DIV, %, MOD -, + & | =, , >=, >,
Read MoreHow can we stuff a string with another one using MySQL functions?
MySQL have two functions namely LPAD() and RPAD() with the help of which we can stuff a string with another string.LPAD() function, as the name suggests, left stuff a string with another string. Following is the syntax for using it in MySQL −SyntaxLPAD(original_string, @length, pad_string)Here, original_string is the string in which we stuff another string.@length is the total length of string returned after stuffing.Pad_string is the string which is to be stuffed with original_string.Examplemysql> SELECT LPAD('tutorialspoint', 18, 'www.'); +----------------------------------+ | LPAD('tutorialspoint', 18, 'www.') | +----------------------------------+ | www.tutorialspoint | +----------------------------------+ 1 row in set ...
Read MoreHow can we check for NULL in a MySQL query?
With the help of IS NULL operator, we can check for NULL in a MySQL query. We cannot use = (comparison operator) because as we know that NULL is not a value. Following example using the data from ‘employee’ table will exhibit it −Examplemysql> Select * from Employee WHERE Salary IS NULL; +----+-------+--------+ | ID | Name | Salary | +----+-------+--------+ | 7 | Aryan | NULL | | 8 | Vinay | NULL | +----+-------+--------+ 2 rows in set (0.00 sec)The query above use IS NULL operator and produces the output where salary column is having NULL.mysql> ...
Read MoreHow can I use RAND() function in an ORDER BY clause to shuffle MySQL set of rows?
When we use MySQL ORDER BY clause with RAND() function then the result set would have the shuffled set of rows. In other words, the result set would be in a random order. To understand it considers a table ‘Employee’ having the following records −mysql> Select * from employee; +----+--------+--------+ | ID | Name | Salary | +----+--------+--------+ | 1 | Gaurav | 50000 | | 2 | Rahul | 20000 | | 3 | Advik | 25000 | | 4 | Aarav | 65000 | | 5 | Ram | 20000 | | 6 | Mohan | ...
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