Database Articles - Page 218 of 618

For this, use REGEXP_REPLACE(). Let us first create a table −mysql> create table DemoTable1595    -> (    -> StudentCode varchar(50)    -> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1595 values('200 John'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1595 values('101 Carol/400 Taylor'); Query OK, 1 row affected (0.72 sec) mysql> insert into DemoTable1595 values('101 302 405 Sam/9870'); Query OK, 1 row affected (0.28 sec)Display all records from the table using select statement −mysql> select * from DemoTable1595;This will produce the following output −+----------------------+ ... Read More

To select the nth highest value in MySQL, following is the syntax −select distinct(yourColumnName) from yourTableName order by yourColumnName DESC limit (NthValue-1), 1;Let us first create a table −mysql> create table DemoTable1594    -> (    -> Marks int    -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1594 values(76); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1594 values(95); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1594 values(56); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1594 values(96); Query OK, ... Read More

Use IF() method as an alternative to CASE WHEN in MySQL. Let us first create a table −mysql> create table DemoTable1593    -> (    -> PlayerScore int    -> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1593 values(78); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1593 values(0); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1593 values(89); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1593 values(0); Query OK, 1 row affected (0.16 sec)Display all records from the table using ... Read More

For this, set conditions using MySQL IF(). Let us first create a table −mysql> create table DemoTable1592    -> (    -> StudentMarks int    -> ); Query OK, 0 rows affected (0.76 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1592 values(56); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1592 values(NULL); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1592 values(98); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1592 values(0); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1592 values(75); Query OK, 1 row affected ... Read More

For this, you can use TIME_FORMAT(). Let us first create a table −mysql> create table DemoTable1591    -> (    -> ArrivalTime varchar(20)    -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1591 values('1620'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1591 values('2345'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1591 values('2210'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select * from DemoTable1591;This will produce the following output −+-------------+ | ArrivalTime | +-------------+ ... Read More

Following is the syntax to combine two fields in MySQL −alter table yourTableName add column yourColumnName dataType;  update yourTableName set yourAddedColumnName =concat(yourColumnName1, ' ', yourColumnName2);Let us first create a table −mysql> create table DemoTable1590    -> (    -> FirstName varchar(20),    -> LastName varchar(20)    -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1590 values('Adam', 'Smith'); Query OK, 1 row affected (0.45 sec) mysql> insert into DemoTable1590 values('John', 'Doe'); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable1590 values('David', 'Miller'); Query OK, 1 row affected ... Read More

You cannot create database with numeric name as shown below −mysql> create database 1233;This will produce the following output −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1233' at line 1To create a database with numeric name, you need to use backticks around the database name −create database yourDatabaseName;Let us implement the above syntax −mysql> create database `1233`; Query OK, 1 row affected (0.20 sec)Now you can switch to the same database −mysql> use `1233`; Database changed

For every single statement on MySQL command line, it shows the exact time to execute the specific statement.Let us first create a table −mysql> create table DemoTable1589    -> (    -> EmployeeId int,    -> EmployeeName varchar(20)    -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1589 values(101, 'Sam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1589 values(102, 'Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1589 values(103, 'David'); Query OK, 1 row affected (0.16 sec)Display all records from the table ... Read More

To select maximum of sum of two columns, use aggregate function MAX() along with subquery. Let us first create a table −mysql> create table DemoTable1587    -> (    -> Value1 int,    -> Value2 int    -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1587 values(30, 50); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1587 values(80, 90); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1587 values(40, 67); Query OK, 1 row affected (0.13 sec)Display all records from the table using select ... Read More

To display information about field names, the syntax is as follows −show columns from yourTableName;Let us first create a table −mysql> create table DemoTable1586    -> (    -> EmployeeId int,    -> EmployeeFirstName varchar(20),    -> EmployeeLastName varchar(20),    -> EmployeeAge int,    -> EmployeeCountryName varchar(20),    -> EmployeeSalary int    -> ); Query OK, 0 rows affected (0.78 sec)Following is the query to display field names −mysql> show columns from DemoTable1586;This will produce the following output −+---------------------+-------------+------+-----+---------+-------+ | Field               | Type        | Null | Key | Default | ... Read More