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Database Articles
Page 293 of 546
Update MySQL column based on email address?
Let us first create a table −mysql> create table DemoTable -> ( -> EmailAddress varchar(20), -> Score int -> ); Query OK, 0 rows affected (1.05 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris@gmail.com', 67); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('Robert@gmail.com', 57); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('David@gmail.com', 98); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------------------+-------+ | EmailAddress ...
Read MoreHow to update MySQL table storage engine
To update MySQL table engine, following the below syntax −Syntaxalter table yourTableName ENGINE=InnoDB;Let us first create a table −mysql> create table DemoTable -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20), -> StudentAge int, -> StudentCountryName varchar(20) -> )ENGINE=MyISAM, AUTO_INCREMENT=101; Query OK, 0 rows affected (0.18 sec)Let us check the description of table −mysql> show create table DemoTable;This will produce the following output −+---------------+-----------------------------------------------------------------------------------------+ | Table | Create Table ...
Read MoreFetch maximum individual marks for a student with marks1 and marks2 records in MySQL?
For this, use MAX() along with GROUP BY clause. Let us first create a table −mysql> create table DemoTable -> ( -> StudentEmailId varchar(20), -> Marks1 int, -> Marks2 int -> ); Query OK, 0 rows affected (0.90 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John@gmail.com', 45, 32); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable values('John@gmail.com', 32, 45); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values('Carol@gmail.com', 32, 45); Query OK, 1 row affected (1.64 sec) mysql> insert into DemoTable values('David@gmail.com', 45, 32); ...
Read MoreSelect the maximum for each value in a MySQL table?
For this, use GROUP BY clause along with MAX(). Let us first create a table −mysql> create table DemoTable -> ( -> CountryName varchar(20), -> Population int -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('US', 560); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('UK', 10090); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('UK', 8794); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('US', 1090); Query OK, 1 row affected (0.21 sec)Display ...
Read MoreDoes grant on *.* apply to databases created after the grant in MySQL?
Yes, since this is a global privilege. Let us first create a user −mysql> CREATE USER 'Jace'@'localhost' IDENTIFIED BY 'Jace123'; Query OK, 0 rows affected (0.67 sec)Here is the query to grant for global privileges with *.*:mysql> GRANT SELECT ON *.* TO 'Jace'@'localhost'; Query OK, 0 rows affected (0.58 sec)Now you can show all grants for a user −mysql> show grants for 'Jace'@'localhost';This will produce the following output −+-------------------------------------------+ | Grants for Jace@localhost | +-------------------------------------------+ | GRANT SELECT ON *.* TO `Jace`@`localhost` | +-------------------------------------------+ 1 row in set (0.14 sec)
Read MoreMySQL query to sort by both timestamp and enum?
For this, you can use ORDER BY DATE(). Let us first create a table. Here, we have a column with type DATE and another with type ENUM −mysql> create table DemoTable -> ( -> JoiningDate date, -> Status ENUM('Good', 'Excellent', 'Bad') -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-21', 'Excellent'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Status) values('Bad'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Status) values('Good'); Query OK, 1 row affected (0.13 sec)Display all ...
Read MoreHow to use a select statement while updating in MySQL?
For this, use sub query along with WHERE clause while using the MySQL UPDATE command. Let us first create a table −mysql> create table DemoTable -> ( -> Id int, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Chris'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(250, 'David'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values(150, 'Mike'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select ...
Read MoreQuery results that have less than X characters in MySQL?
You can use CHAR_LENGTH() along with the WHERE clause. Let us first create a table −mysql> create table DemoTable -> ( -> FullName varchar(50) -> ); Query OK, 0 rows affected (1.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris Brown'); Query OK, 1 row affected (0.40 sec) mysql> insert into DemoTable values('David Miller'); Query OK, 1 row affected (0.91 sec) mysql> insert into DemoTable values('Robert Miller'); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values('John Smith'); Query OK, 1 row affected (0.89 sec)Display all records from the ...
Read MoreHow to split a column in MySQL?
To split a column, you need to use SUBSTRING_INDEX() in MySQL. Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(40) -> ); Query OK, 0 rows affected (1.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John_Smith'); Query OK, 1 row affected (0.36 sec) mysql> insert into DemoTable values('Carol_Taylor'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values('David_Miller'); Query OK, 1 row affected (0.54 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------------+ ...
Read MoreAdd a single year to all the date records in a MySQL table column
Let us first create a table −mysql> create table DemoTable -> ( -> JoiningDate datetime -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2015-01-21'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('2017-04-02'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('2018-12-31'); Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+---------------------+ | JoiningDate | +---------------------+ | 2015-01-21 00:00:00 ...
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