The easiest way to get number of rows, use aggregate function COUNT(*). Let us first create a table −mysql> create table DemoTable1575    -> (    -> FirstName varchar(20)    -> ); Query OK, 0 rows affected (1.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1575 values('Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1575 values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1575 values('Adam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1575 values('Robert'); Query OK, 1 row affected (0.15 sec)Display all records from the table ... Read More

Let us first create a table −mysql> create table DemoTable1574    -> (    -> StudentCode varchar(20)    -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1574 values('111_Carol'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1574 values('______'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable1574 values('David_12345'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1574 values('______'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select * from DemoTable1574;This will produce the following ... Read More

To retrieve table names from a database in MySQL, the syntax is as follows −show tables from yourDatabaseName;Let us implement the above query in order to retrieve table names from a database in MySQL −mysql> show tables from hb_student_tracker;This will produce the following output −+------------------------------+ | Tables_in_hb_student_tracker | +------------------------------+ | demotable192                 | | demotable193                 | | demotable194                 | | demotable195                 | | demotable196           ... Read More

Let us first create a table −mysql> create table DemoTable1572    -> (    -> StudentId int,    -> StudentMarks int,    -> StudentName varchar(20)    -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1572 values(1, 79, 'Sam'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1572 values(2, 89, 'Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1572 values(3, 98, 'David'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1572 values(4, 79, 'Bob'); Query OK, 1 row affected (0.10 sec)Display all ... Read More

To insert an IF statement into a MySQL query, use the below syntax::select yourColumnName ,if(yourCondition, yourStatement1, yourStatement2) from yourTableName;Let us first create a table −mysql> create table DemoTable1571    -> (    -> Id int,    -> Value int    -> ); Query OK, 0 rows affected (5.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1571 values(101, 500); Query OK, 1 row affected (1.07 sec) mysql> insert into DemoTable1571 values(102, 450); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable1571 values(103, 300); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1571 ... Read More

Let us first create a table −mysql> create table DemoTable1570    -> (    -> ArrivalTime datetime    -> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1570 values('2019-10-15 5:10:00'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable1570 values('2019-10-15 23:00:00'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1570 values('2019-10-15 23:10:00'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1570 values('2019-10-15 16:10:00'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select * from DemoTable1570;This ... Read More

Let us first create a table −mysql> create table DemoTable1569    -> (    -> StudentId varchar(10),    -> StudentName varchar(20)    -> ); Query OK, 0 rows affected (3.05 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1569 values('John_12', 'John Smith'); Query OK, 1 row affected (0.38 sec) mysql> insert into DemoTable1569 values('David_321', 'Carol Taylor'); Query OK, 1 row affected (0.50 sec) mysql> insert into DemoTable1569 values('David_989', 'David Miller'); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select * from DemoTable1569;This will produce the following output+-----------+--------------+ | ... Read More

To fetch total number of table rows across databases, use aggregate function SUM() along with INFORMATION SCHEMA. Let us first create a table, which is in “web” database −mysql> create table DemoTable1568    -> (    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1568 values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1568 values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1568 values('David'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select ... Read More

To get the last 30 rows in MySQL, you need to use ORDER BY DESC and then LIMIT 30. The syntax is as follows −select * from yourTableName order by yourColumnName DESC LIMIT 30;Let us first create a table −mysql> create table DemoTable1567    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY    -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1567 values(), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ... Read More

For this, you can use CASE WHEN statement. Let us first create a table −mysql> create table DemoTable    -> (    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(''); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(''); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> ... Read More