This error occurs when you drop a user with localhost while you have created a user with ‘%’.Let us create a user with ‘%’ and drop the user as a localhost. The syntax is as followsCREATE USER 'yourUserName'@'%' IDENTIFIED BY 'yourPassword';Let us create a user using the above syntax. The query to create a user is as followsmysql> CREATE USER 'Jack'@'%' IDENTIFIED BY '1234'; Query OK, 0 rows affected (0.26 sec)Check user is created successfully or notmysql> select user, host from MySQL.user;The following is the output+------------------+-----------+ | user             | host      | +------------------+-----------+ ... Read More

You can use SUBSTRING() from MySQL to limit length of strings. The syntax is as followsSELECT SUBSTRING(yourColumnName, 1, yourIntegerValueToGetTheCharacters) as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table limitLengthOfLongTextDemo -> ( -> sentence LONGTEXT -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The query is as followsmysql> insert into limitLengthOfLongTextDemo values('This is the introduction to MySQL'); Query OK, 1 row affected (0.17 sec) mysql> insert into ... Read More

You can use multiplication operator (*) between two cells. The syntax is as followsSELECT yourColumnName1, yourColumnName2, yourColumnName1*yourColumnName2 as ‘anyVariableName’ from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table MultiplicationDemo    -> (    -> FirstPrice int,    -> SecondPrice int    -> ); Query OK, 0 rows affected (0.63 sec)Now you can display all records from the table using insert command. The query is as followsmysql> insert into MultiplicationDemo values(10, 2); Query OK, 1 row affected (0.17 sec) mysql> insert into MultiplicationDemo values(4, 2); Query OK, ... Read More

To select last 20 records in ascending order, you can use subquery LIMIT clause. The syntax is as followsSELECT *FROM (    SELECT *FROM yourTableName ORDER BY yourColumnName desc limit 20 ) anyVariableName order by anyVariableName.yourColumnName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table ProductInformation    -> (    -> ProductId int,    -> ProductName varchar(100),    -> ProductPrice int    -> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command. The query is as followsmysql> insert into ProductInformation values(101, 'Product-1', ... Read More

You can add a not null column at the time of table creation or you can use it for an existing table.Case 1 − Add a not null column at the time of creating a table. The syntax is as followsCREATE TABLE yourTableName (    yourColumnName1 dataType NOT NULL,    yourColumnName2 dataType    .      .    .    N );The query to create a table is as followsmysql> create table NotNullAtCreationOfTable    -> (    -> Id int not null,    -> Name varchar(100)    -> ); Query OK, 0 rows affected (0.60 sec)In the above table, we ... Read More

You can combine the insert, values and select statement using below syntaxinsert into yourFirstTableName(yourColumnName1, yourColumnName2, .......N) select yourColumnName1, yourColumnName2, .......N from yourSecondTableName where yourCondition;To understand the above syntax, let us create two tables in which first table will get the record from the second table.Let us create the first table without any records. The query to create a table is as followsmysql> create table CombiningInsertValuesSelect    -> (    -> EmployeeId varchar(10),    -> EmployeeName varchar(100),    -> EmployeeAge int    -> ); Query OK, 0 rows affected (6.95 sec)Now you can create the second table with some records. The ... Read More

To insert decimal into MySQL, you can use DECIMAL() function from MySQL. The syntax is as followsyourColumnName DECIMAL(TotalDigit, DigitAfterDecimalPoint);To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table DecimalInsert    -> (    -> Id int,    -> Name varchar(100),    -> Amount DECIMAL(4, 2)    -> ); Query OK, 0 rows affected (0.65 sec)Insert the decimal value using insert command. The query is as followsmysql> insert into DecimalInsert values(1, 'John', 12.4); Query OK, 1 row affected (0.15 sec) mysql> insert into DecimalInsert values(2, 'Carol', 12.34); Query OK, ... Read More

You can declare a variable using @anyVariablename which is a session variable. To create a session variable, you need to use SET command.The syntax is as followsSET @anyVariableName:=anyValue;You can declare a local variable using DECLARE command. The syntax is as followsDECLARE yourVariableName datatypeYou can set the default value at the time of creating a variable. The syntax is as followsDECLARE yourVariableName datatype default ‘yourValue’Here is the demo of session variable. To understand it, let us create a table.The query to create a table is as followsmysql> create table SessionVariableDemo    -> (    -> EmployeeId varchar(10),    -> EmployeeName varchar(30), ... Read More

You can use backward slash followed by G i.e. \G instead of semicolon(;). The syntax is as follows to display database names vertically in MySQL command lineSHOW DATABASES \GTo display all database names vertically, you need to use \G. The query is as followsmysql> show databases\GThe following is the output*************************** 1. row *************************** Database: business *************************** 2. row *************************** Database: database1 *************************** 3. row *************************** Database: databasesample *************************** 4. row *************************** Database: education *************************** 5. row *************************** Database: hello *************************** 6. row *************************** Database: information_schema *************************** 7. row *************************** Database: javadatabase2 *************************** 8. row *************************** Database: javasampledatabase *************************** 9. row ... Read More

You can use backward slash followed by G i.e. \G instead of semicolon(;). The syntax is as follows to show records vertically in MySQL command line.SELECT *FROM yourTableName\GTo understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table showRecordsVertically -> ( -> Id int, -> Name varchar(100), -> Age int -> ); Query OK, 0 rows affected (2.10 sec)Insert some records in the table using insert command. The query is as followsmysql> insert into showRecordsVertically ... Read More