Let us first create a table −mysql> create table DemoTable (    CustomerName varchar(100),    CustomerCountryName varchar(100) ); Query OK, 0 rows affected (0.95 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 'US'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Bob', 'UK'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Carol', NULL); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('David', 'AUS'); Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable values('Mike', NULL); Query OK, 1 row affected (0.18 sec)Display all records ... Read More

You can use concat(). Let us first create a table −mysql> create table DemoTable (    Value int ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(100); Query ... Read More

For this, you can use LENGTH() along with REPLACE(). Let us first create a table −mysql> create table DemoTable (    Value int ); Query OK, 0 rows affected (1.22 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10002000); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(00000); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(400560); Query OK, 1 row affected (0.19 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----------+ | Value    | +----------+ | 10002000 ... Read More

For this, you can use IFNULL(). Let us first create a table −mysql> create table DemoTable (    FirstName varchar(100),    LastName varchar(100) ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', 'Doe'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable values(NULL, 'Taylor'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('David', NULL); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(NULL, 'Miller'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> ... Read More

For this, you can use IFNULL(). Let us first create a table −mysql> create table DemoTable (    Value1 int,    Value2 int ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, NULL); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(20, 40); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values(3, NULL); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------+--------+ | Value1 | Value2 ... Read More

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

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