This is a type of comment. The /* is the beginning of a comment and */ is the end of comment.Let us implement and display how to create a commentmysql> /* This is the first MySQL Program */MySQL will ignore the above comment.Let us see an example. Here, we have written a comment with /* and */mysql> /*This table has information about person */ mysql> create table DemoTable (    PersonId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    PersonName varchar(20),    PersonAge int ); Query OK, 0 rows affected (0.58 sec)

You can use LENGTH() to count number of specific symbols in a row. Let us first create a table −mysql> create table DemoTable (    Value varchar(200) ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('?1234?6789?5656?324?'); Query OK, 1 row affected (0.17 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----------------------+ | Value | +----------------------+ | ?1234?6789?5656?324? | ... Read More

You can use update command along with a user-defined variable. Let us first create a table −mysql> create table DemoTable (    FirstName varchar(20),    Position int ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 100); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Robert', 120); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('David', 130); Query OK, 1 row affected (0.16 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce ... Read More

To convert date YYYYMMDD to YY-MM-DD in MySQL, use the below syntax −select date_format(str_to_date(yourColumnName, '%Y%m%d'), '%Y-%m-%d') from yourTableName;Let us first create a table −mysql> create table DemoTable (    ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    ClientProjectDeadline varchar(200) ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command. We have inserted dates in the YYYYMMDD format −mysql> insert into DemoTable(ClientProjectDeadline) values('20121221'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(ClientProjectDeadline) values('20190416'); Query OK, 1 row affected (0.53 sec) mysql> insert into DemoTable(ClientProjectDeadline) values('20160624'); Query OK, 1 row affected (0.20 sec) mysql> ... Read More

You can use IN() to display all records except one in MySQL. Let us first create a table −mysql> create table DemoTable (    Id int,    FirstName varchar(20) ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Larry'); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable values(10, 'Chris'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(110, 'Robert'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(90, 'David'); Query OK, 1 row affected (0.20 sec)Following is the query ... Read More

In order to get the greatest of two columns values in MySQL, you need to use GREATEST() function. Following is the syntax:select greatest(yourColumnName1, yourColumnName2) AS anyAliasName from yourTableName; Let us first create a table:mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Number1 int,    Number2 int ); Query OK, 0 rows affected (0.63 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(Number1, Number2) values(1000, 10000); Query OK, 1 row affected (0.49 sec) mysql> insert into DemoTable(Number1, Number2) values(600, 900); Query OK, 1 row affected (0.12 sec) mysql> ... Read More

Let us first create a table with Id as auto_increment −mysql> create table DemoTable (    UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    UserName varchar(20) ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName) values('John'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(UserName) values('Larry'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable(UserName) values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(UserName) values('Bob'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(UserName) values('Carol'); Query OK, 1 row affected ... Read More

You can use SHOW command for this. Following is the syntax −show columns from yourTableName;Let us first create a table −mysql> create table DemoTable (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentFirstName varchar(20),    StudentLastName varchar(20),    StudentAge int,    StudentAddress varchar(200) ); Query OK, 0 rows affected (0.54 sec)Following is the query to get the names of my MySQL table columns −mysql> show columns from DemoTable;This will produce the following output −+------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null ... Read More

You can use ORDER BY IF() to get records in a certain order. Let us first create a table:mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    FirstName varchar(20),    Branch varchar(20) ); Query OK, 0 rows affected (1.96 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(FirstName, Branch) values('John', 'CS'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable(FirstName, Branch) values('Carol', 'ME'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(FirstName, Branch) values('David', 'ME'); Query OK, 1 row affected (0.11 sec) mysql> ... Read More

You can use TRUNCATE() method to floor the values instead of round. Let us first create a table −mysql> create table DemoTable (    Value DECIMAL(20, 8) ); Query OK, 0 rows affected (0.54 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(23.5654433); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(12.345542211); Query OK, 1 row affected, 1 warning (0.21 sec) mysql> insert into DemoTable values(12345.678543); Query OK, 1 row affected (0.22 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the ... Read More