Articles on Trending Technologies

Technical articles with clear explanations and examples

How to create conditions in a MySQL table with multiple columns?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 396 Views

For conditions, use IF(). Following is the syntax −IF(yourCondition, trueStatement, falseStatement);Let us first create a table −mysql> create table DemoTable612 (Number1 int, Number2 int, Score int); Query OK, 0 rows affected (0.47 sec)Insert some records in the table using insert command −mysql> insert into DemoTable612 values(10, 20, 1000); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable612 values(30, 40, 500); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable612 values(50, 70, 1200); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable612 values(100, 120, 400); Query OK, 1 row affected (0.16 sec)Display all records from ...

Read More

Selecting the top occurring entries in MySQL from a table with duplicate values?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 161 Views

Let us first create a table −mysql> create table DemoTable610 (SubjectName varchar(100)); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable610 values('MySQL'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable610 values('Java'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable610 values('MySQL'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable610 values('MongoDB'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable610 values('MySQL'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable610 values('MySQL'); Query OK, 1 row affected (0.08 sec) mysql> ...

Read More

MySQL ORDER BY with EXPLAIN command

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 196 Views

Let us first create a table −mysql> create table DemoTable606 (Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(100)); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable606(FirstName) values('John'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable606(FirstName) values('Robert'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable606(FirstName) values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable606(FirstName) values('David'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable606;This will produce the following output −+----+-----------+ ...

Read More

Format date to display month names with the entire date in MySQL?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 193 Views

For this, you can use DATE_FORMAT(). Let us first create a table −mysql> create table DemoTable605 (DueDate date); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable605 values('2019-01-21'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable605 values('2019-02-23'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable605 values(curdate()); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable605;This will produce the following output −+------------+ | DueDate    | +------------+ | 2019-01-21 | | 2019-02-23 | | 2019-03-04 ...

Read More

MySQL Quoted table/field names vs unquoted names?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 235 Views

Any identifiers like tablename, stored procedure, viewname or column etc. may be quoted or unquoted. When an identifier is a reserved keyword then you must quote it, else an error would occur.Let us first create a table. Here, we have taken field names as reserved keywords −mysql> create table `INT` (`select` int, `varchar` varchar(100)); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into `INT` values(1, 'MySQL'); Query OK, 1 row affected (0.14 sec) mysql> insert into `INT` values(2, 'MongoDB'); Query OK, 1 row affected (0.34 sec) mysql> insert into `INT` values(3, ...

Read More

Retrieve records whenever a column value starts with 2 vowel letters in MySQL

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 141 Views

Let us first create a table −mysql> create table DemoTable664 (CityName varchar(100)); Query OK, 0 rows affected (0.89 sec)Insert some records in the table using insert command −mysql> insert into DemoTable664 values('Springfield'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable664 values('Austin'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable664 values('Franklin'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable664 values('OAKLAND'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable664 values('Anchorage'); Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −mysql> select *from DemoTable664;This will ...

Read More

How to separate last name and first names in single column into two new columns in MySQL?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 3K+ Views

For this, use SUBSTRING_INDEX() and REPLACE(). Let us first create a table −mysql> create table DemoTable (Name varchar(100)); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command. Here, we have inserted last name and first names −mysql> insert into DemoTable values('Chris | Bob Brown'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Carol | Robert Taylor'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('Sam | David Miller'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will ...

Read More

Best way to combine multiple advanced MySQL select queries?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 466 Views

To combine multiple advanced MySQL select queries, use UNION. Let us first create a table −mysql> create table DemoTable1 (Value1 int, Value2 int); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(10, 29); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1 values(100, 190); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1 values(40, 101); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following output −+--------+--------+ | Value1 | Value2 | ...

Read More

How to implement the opposite of INITCAP() functionality with MySQL?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 318 Views

The INITCAP() method display the first character in every word in uppercase and rest in lowercase.To implement the opposite functionality, you need to create your own function in MySQL. Here’s the function −mysql> delimiter // mysql> create function convertFirstLetterToLowerAndRemainingToCapital(value varchar(250))    returns varchar(250)    deterministic    begin    declare valueLength int;    declare l int;    set valueLength = char_length(value);    set value = upper(value);    set l = 0;    while (l < valueLength ) do       if (mid(value, l ,1) = ' ' or l = 0) then          if (l < valueLength ...

Read More

How can I install or enable innoDB in MySQL?

AmitDiwan
AmitDiwan
Updated on 22-Aug-2019 2K+ Views

In order to enable innoDB in MySQ, you need to work around my.ini file. However, in MySQL version 8, the default storage engine is innoDB. Check the same from my.ini file −You can even set this at the time of table creation −mysql> create table DemoTable    (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentFirstName varchar(100),    StudentLastName varchar(100),    StudentAge int    ) ENGINE=InnoDB; Query OK, 0 rows affected (1.66 sec)Let us now run a query to check the engine type of specific table −mysql> select table_name, engine from information_schema.tables where table_name="DemoTable";This will produce the following ...

Read More
Showing 56251–56260 of 61,248 articles
Advertisements