Following is the declaration for a UNIQUE clause in MySQL −create table yourTableName (    yourColumnName1 dataType,    yourColumnName2 dataType,    UNIQUE(yourColumnName1),    UNIQUE(yourColumnName1) );Let us first create a table −mysql> create table DemoTable (    Value int,    Value2 int,    UNIQUE(Value),    UNIQUE(Value2) ); Query OK, 0 rows affected (13.98 sec)Insert some records in the table using insert command. Here, duplicate records won’t insert because we have used UNIQUE above −mysql> insert into DemoTable values(10, 20) ; Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable values(10, 30); ERROR 1062 (23000): Duplicate entry '10' for key ... Read More

Let us first create a table −mysql> create table DemoTable (    AdmissionDate datetime ); Query OK, 0 rows affected (8.99 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.46 sec) mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.71 sec) mysql> insert into DemoTable values('2010-01-12 12:30:45'); Query OK, 1 row affected (1.22 sec) mysql> insert into DemoTable values('2010-01-20 12:30:45'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2010-01-20 ... Read More

In this section we will see how to check whether a number is Palindrome or not using the PL/SQL. In PL/SQL code, some group of commands are arranged within a block of related declaration of statements.A number is palindrome if the number, and the reverse of that number are same. Suppose a number 12321, this is palindrome, but 12345 is not a palindrome.ExampleDECLARE    n number;    m number;    temp number:=0;    rem number; BEGIN    n :=12321;    m :=n;    while n>0    loop       rem := mod(n, 10);       temp := (temp*10)+rem; ... Read More

Let’s say we have a database “web” and we need to get all the tables having a specific column ’StudentFirstName’.For this, below is the query −mysql> select myColumnName.table_name from information_schema.columns myColumnName where myColumnName.column_name = 'StudentFirstName' and table_schema='web';This will produce the following output −+---------------+ | TABLE_NAME | +---------------+ | demotable109 | | demotable297 | | demotable335 | | demotable395 | | demotable418 | | demotable425 | | demotable436 | +---------------+ 7 rows in set (0.14 sec)Therefore, the above tables have one of the column names as “StudentFirstName”.Let us check the description ... Read More

To convert MySQL timestamp to UNIX Timestamp, use the UNIX_TIMESTAMP(). Following is the syntax −select unix_timestamp(yourColumnName) from yourTableName;Let us first create a table −mysql> create table DemoTable(    Duetimestamp timestamp ); Query OK, 0 rows affected (2.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(now()); Query OK, 1 row affected (1.53 sec) mysql> insert into DemoTable values('2016-01-21 12:34:00'); Query OK, 1 row affected (0.73 sec) mysql> insert into DemoTable values('2018-05-01 02:00:00'); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable values('2017-03-02 01:10:20'); Query OK, 1 row affected (10.19 sec)Display all records from ... Read More

To replace & with an ampersand, use MySQL REPLACE(). Let us first create a table −mysql> create table DemoTable(    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Value varchar(100) ); Query OK, 0 rows affected (1.06 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Value) values('@amp'); Query OK, 1 row affected (0.33 sec) mysql> insert into DemoTable(Value) values('&'); Query OK, 1 row affected (1.09 sec) mysql> insert into DemoTable(Value) values('#amp'); Query OK, 1 row affected (0.28 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----+-------+ ... Read More

Let us first create a table −mysql> create table DemoTable(    Value int,    Value2 varchar(100) ); Query OK, 0 rows affected (0.84 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, '999.999.999.999'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(20, '888.888.888.888'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(30, '999.999.999.999'); Query OK, 1 row affected (0.09 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-------+-----------------+ | Value | Value2 ... Read More

Yes, we can do that. Let us first create a table −mysql> create table DemoTable(    Id int ); Query OK, 0 rows affected (1.02 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(201); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(202); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(290); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(301); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------+ ... Read More

The @@identity returns the last inserted value in the auto_increment column in the current session. Let us first create a table −mysql> create table DemoTable(    UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    UserName varchar(100) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName) values('David'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(UserName) values('Mike'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(UserName) values('Carol'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(UserName) values('Robert'); Query OK, 1 row affected (0.24 sec) ... Read More

Let us first create a table −mysql> create table DemoTable(    ProductName varchar(100),    ProductPrice int ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Product-1', 56); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Product-2', 78); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('Product-1', 88); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Product-2', 86); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Product-1', 45); Query OK, 1 row affected (0.18 sec) mysql> insert into ... Read More