For this, use UNION more than once in a single MySQL query. Let us first create a table −mysql> create table DemoTable    -> (    -> Value1 int,    -> Value2 int,    -> Value3 int    -> ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(20, null, null); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(20, null, null); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(20, null, null); Query OK, 1 row affected (0.12 sec) mysql> insert into ... Read More

CASE statement with the WHEN clause is used to work around conditions. Following is the syntax−select *,    case when yourCondition then yourStatement    when yourCondition then yourStatement    .    . else yourStatement from yourTableName;Let us first create a table −mysql> create table DemoTable    -> (    -> StudentName varchar(20),    -> StudentMarks int    -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 78); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('Robert', 88); Query OK, 1 row affected (0.14 sec) ... Read More

To replace duplicate records and avoid any error while inserting, use INSERT ON DUPLICATE KEY UPDATE. Let us first create a table −mysql> create table DemoTable    -> (    -> Id int,    -> Name varchar(20),    -> UNIQUE(Id, Name)    -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(101, 'Chris') on duplicate key update Id=10001, Name='Robert'; Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(102, 'Mike') on duplicate key update Id=10001, Name='Robert'; Query OK, 1 row affected (0.17 sec) mysql> insert into ... Read More

Yes, we can turn a column records into a list using the MySQL GROUP_CONCAT(). Let us first create a table −mysql> create table DemoTable    -> (    -> ClientId int,    -> ClientName varchar(20)    -> ); Query OK, 0 rows affected (0.88 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Chris'); Query OK, 1 row affected (0.54 sec) mysql> insert into DemoTable values(100, 'Robert'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(100, 'Adam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(100, 'David'); Query OK, ... Read More

To create a temporary table with dates, use the CREATE TEMPORARY TABLE in MySQL. Following is the syntax −Syntaxcreate temporary table yourTableName(    yourColumnName datetime );Let us first create a table −mysql> create temporary table DemoTable    -> (    -> DueDate datetime    -> ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(now()); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable values(curdate()); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable values('2018-01-21'); Query OK, 1 row affected (0.00 sec) mysql> insert into ... Read More

To increase item value for multiple items in a single query, you can use the CASE statement in MySQL. Let us first create a table −mysql> create table DemoTable    -> (    -> ProductName varchar(20),    -> ProductPrice int    -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Product-1', 700); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('Product-2', 1000); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Product-3', 3000); Query OK, 1 row affected (0.10 sec)Display all records from ... Read More

For this, you can use GROUP BY HAVING along with the COUNT(*) function. Let us first create a table −mysql> create table DemoTable    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.47 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable ... Read More

It would be good to use IN() instead of multiple OR statements. Let us first create a table −mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> FirstName varchar(20)    -> ); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstName) values('John'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(FirstName) values('Adam'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable(FirstName) values('David'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable(FirstName) values('Mike'); Query OK, 1 ... Read More

To implement custom sort order in MySQL, you need to use ORDER BY FIELD(). Let us first create a table −mysql> create table DemoTable    -> (    -> Designation varchar(100)    -> ); Query OK, 0 rows affected (1.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Software Engineer'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Associate Software Engineer'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values('Software Development Engineer'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Product Manager'); Query OK, 1 row ... Read More

To subtract a day in MySQL, use the DATE_SUB() method. Let us first create a table −mysql> create table DemoTable    -> (    -> AdmissionDate timestamp    -> ); Query OK, 0 rows affected (1.05 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-01'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('2018-12-31'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('2017-03-13'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2019-01-02'); Query OK, 1 row affected (0.08 sec)Display all records from the table using select ... Read More