For this, you can use subquery along with EXISTS. Let us first create a table −mysql> create table DemoTable1    -> (    -> Id int,    -> SubjectName varchar(20)    -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(111, 'MySQL'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1 values(112, 'MongoDB'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(113, 'Java'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1 values(114, 'C'); Query OK, 1 row affected (0.27 sec) ... Read More

To count, use aggregate function SUM() and to count with condition, you need to set the condition with WHERE. Let us first create a table −mysql> create table DemoTable1515    -> (    -> ClientId varchar(10),    -> ClientName varchar(20)    -> ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1515 values('CLI-101', 'Chris'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1515 values('CLI-110', 'David'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1515 values('CLI-101', 'Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into ... Read More

For this, you can use the concept of LIMIT and OFFSET. Let us first create a table −mysql> create table DemoTable1514    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> FirstName varchar(20)    -> ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1514(FirstName) values('Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1514(FirstName) values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1514(FirstName) values('Sam'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1514(FirstName) values('Mike'); Query OK, 1 row ... Read More

If you do not specify the column list in insert statement then you can use below syntax −insert into yourTableName values(NULL, yourValue, NULL, NULL, .....N);Let us first create a table −mysql> create table DemoTable1513    -> (    -> StudentId int,    -> StudentName varchar(20) ,    -> StudentAge int,    -> StudentCountryName varchar(20)    -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1513 values(NULL, 'Chris Brown', NULL, NULL); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1513 values(101, NULL, NULL, NULL); Query OK, 1 row ... Read More

You can detect with the help of row_count(). If the row_count() returns 1 that means it is a new record. If it returns 2, that means the ON UPDATE event is fired with query. Following is the syntax −select row_count();Let us first create a table −mysql> create table DemoTable1512    -> (    -> Value int ,    -> UNIQUE(Value)    -> ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1512 values(90) on duplicate key update Value=Value+10; Query OK, 1 row affected (0.09 sec)Now you can check the on ... Read More

Fir this, you can use IFNULL() along with ORDER BY clause. Let us first create a table table −mysql> create table DemoTable1511    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> FirstName varchar(20)    -> ); Query OK, 0 rows affected (1.97 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1511(FirstName) values('John'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable1511(FirstName) values('Robert'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable1511(FirstName) values('Mike'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1511(FirstName) values('Robert'); Query OK, 1 ... Read More

Following is the syntax −select length(yourColumnName) - length(replace(yourColumnName, ', ', '')) as anyAliasName from yourTableName;Let us first create a table −mysql> create table DemoTable1510    -> (    -> Value varchar(50)    -> ); Query OK, 0 rows affected (6.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1510 values('20, 35'); Query OK, 1 row affected (0.57 sec) mysql> insert into DemoTable1510 values('45, 67, 89'); Query OK, 1 row affected (0.99 sec) mysql> insert into DemoTable1510 values('90, 97, 101, 190'); Query OK, 1 row affected (1.15 sec)Display all records from the table using select statement −mysql> ... Read More

For this, you can use INTERVAL in MySQL. Let us first create a table −mysql> create table DemoTable1509    -> (    -> ArrivalTime datetime    -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1509 values('2018-01-21 10:20:30'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1509 values('2019-04-01 11:00:00'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1509 values('2015-12-12 05:45:20'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select * from DemoTable1509;This will produce the following output ... Read More

Use @ for variable and concat_ws() to display concatenated result in the table. Let us first create a table −mysql> create table DemoTable1508    -> (    -> StudentFirstName varchar(20),    -> StudentLastName varchar(20)    -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1508 values('Chris', 'Brown'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1508 values('David', 'Miller'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1508 values('John', 'Doe'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> ... Read More

For this, you can use group_concat(). Let us first create a table −mysql> create table DemoTable1507    -> (    -> Name varchar(20),    -> PaperSet int    -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1507 values('Chris', 111); Query OK, 1 row affected (0.37 sec) mysql> insert into DemoTable1507 values('David', 112); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1507 values('Mike', 111); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable1507 values('Bob', 113); Query OK, 1 row affected (0.14 sec)Display all records from ... Read More