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For this, use ORDER BY along with LIMIT. Let us first create a table wherein we have a column with User id, logged in time, and name −mysql> create table DemoTable1911 ( UserId int, UserLoggedInTime time, UserName varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1911 values(100, '7:32:00', 'Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1911 values(101, '5:00:00', 'David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1911 values(102, '6:10:20', 'Mike'); Query OK, 1 row affected (0.00 ... Read More
The exit() function prints a message and exits the current script.Syntaxexit(msg)Parametersmsg − The message to write before exiting the script.ReturnThe exit() function returns nothing.Example
This depends on the requirements in hand.JSON is quicker in comparison to PHP serialization unless the following conditions are met−Deeply nested arrays are stored.The objects that are stored need to be unserialized to a proper class.The interaction is between old PHP versions that don't support json_decode.The below line of code can be used to store PHP arrays using json_encode−json_encode($array, JSON_UNESCAPED_UNICODE)JSON doesn't store the object's original class anywhere, but it can be restored as class instances belonging to stdClass.Why use json_encode instead of serializing?JSON is much more portable in comparison to serialize.The features of __sleep() and __wakeup() can't be leveraged using ... Read More
For this, you can use CASE WHEN statement. Let us first create a table −mysql> create table DemoTable1910 ( FirstName varchar(20), Marks int ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1910 values('Chris', 45); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1910 values('David', 85); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1910 values('Chris', 55); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1910 values('Chris', 98); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1910 values('David', ... Read More
To return list of databases, the syntax is as follows −select schema_name as anyAliasName from information_schema.schemata;Here is the query to return list of databases in MySQL −mysql> select schema_name as DatabaseName from information_schema.schemata;This will produce the following output −+---------------------------+ | DatabaseName | +---------------------------+ | mysql | | information_schema | | performance_schema | | sys | | business | | sample | | hello | | test | | mybusiness | | databasesample | | schemasample | | universitydatabase | | education | | mydatabase | | database1 | | sampledatabase | | test3 | | javadatabase2 | | javasampledatabase | | rdb | | onetomanyrelationship | | webtracker | | web | | commandline | | hb_student_tracker | | bothinnodbandmyisam | | customertracker | | tracker | | demo | | customer_tracker_database | | login | | onlinebookstore | | customer-tracker | | web_tracker | | instant_app | | 1233 | +---------------------------+ 36 rows in set (0.00 sec)
For this, you need to use SET command only once. Let us first create a table −mysql> create table DemoTable1909 ( Id int NOT NULL, FirstName varchar(20), LastName varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1909 values(101, 'John', 'Smith'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1909 values(102, 'John', 'Doe'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1909 values(103, 'Adam', 'Smith'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1909 values(104, 'David', 'Miller'); Query ... Read More
Let us first create a table −mysql> create table DemoTable1908 ( Code text ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1908 values('MySQL(1)Database'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1908 values('MongoDB 2 Database'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1908 values('MySQL(3)Database'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1908 values('SQL Server(10)Database'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1908 values('MySQL 8 Database'); Query OK, 1 row affected (0.00 sec)Display all records from ... Read More
Let us first create a table −mysql> create table DemoTable1907 ( UserId int NOT NULL AUTO_INCREMENT, UserName varchar(20), UserAge int, UserCountryName varchar(20), PRIMARY KEY(UserId) )ENGINE=MyISAM, AUTO_INCREMENT=100; Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1907(UserName, UserAge, UserCountryName) values('Chris', 26, 'US'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1907(UserName, UserAge, UserCountryName) values('David', 38, 'UK'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1907(UserName, UserAge, UserCountryName) values('John', 28, 'AUS'); Query OK, 1 row affected (0.00 sec)Display all records from the ... Read More
To change format of dates, use the DATE_FORMAT() function. Let us first create a table −mysql> create table DemoTable1906 ( DueTime datetime ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1906 values(now()); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1906 values(curdate()); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1906 values('2017-10-11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1906 values('2015-01-12'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1906 values('2018-04-25'); Query OK, 1 row affected (0.00 ... Read More
To fasten the process, you can use INDEX. Let us first create a table −mysql> create table DemoTable1905 ( FirstName varchar(20), LastName varchar(20) , INDEX F_L_Name(FirstName, LastName) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1905 values('John', 'Smith'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1905 values('John', 'Doe'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1905 values('Adam', 'Smith'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1905 values('John', 'Doe'); Query OK, 1 row affected (0.00 sec) ... Read More