Found 4381 Articles for MySQL

Set column charset in MySQL?

Rishi Rathor
Updated on 30-Jul-2019 22:30:24

535 Views

Set column charset using character SET command. The syntax is as follows −ALTER TABLE yourTableName MODIFY youColumName type CHARACTER SET anyCharcaterSetName;You can use character set name utf8 or something elsE. To set column charset, let us first create a table. The query to create a table is as follows −mysql> create table setCharsetDemo −> ( −> FirstName varchar(60) −> ); Query OK, 0 rows affected (2.09 sec)Now you can check the current column character set with the help of show command. The query is as follows −mysql> show create table setCharsetDemo;The ... Read More

Count number of times value appears in particular column in MySQL?

Ankith Reddy
Updated on 30-Jul-2019 22:30:24

12K+ Views

You can use aggregate function count() with group by. The syntax is as follows.select yourColumnName, count(*) as anyVariableName from yourtableName group by yourColumnName;To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table CountSameValue -> ( -> Id int, -> Name varchar(100), -> Marks int -> ); Query OK, 0 rows affected (0.70 sec)Insert records in the table using insert command. The query is as follows.mysql> insert into CountSameValue values(1, 'Sam', 67); Query OK, 1 row affected (0.17 sec) mysql> insert into CountSameValue values(2, 'Mike', 87); Query OK, 1 ... Read More

How to check for duplicates in MySQL table over multiple columns?

George John
Updated on 30-Jul-2019 22:30:24

2K+ Views

To check for duplicates in MySQL, you can use group by having clause. The syntax is as follows.select yourColumnName1, yourColumnName2, ......N, count(*) as anyVariableName from yourTableName group by yourColumnName1, yourColumnName2 having count(*) > 1;To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table DuplicateDemo -> ( -> StudentId int not null, -> StudentFirstName varchar(100), -> StudentLastName varchar(100), -> Primary Key(StudentId) -> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into DuplicateDemo values(1, 'John', 'Smith'); Query ... Read More

How to select sum or 0 if no records exist in MySQL?

Chandu yadav
Updated on 29-Jun-2020 12:27:22

2K+ Views

You can use aggregate function sum() inside COALESCE(). The below syntax returns the sum of all if the record exists otherwise 0 is returned. The syntax is as follows.select COALESCE(sum(yourColumnName2), 0) AS anyVariableName from yourTableName where yourColumnName1 like '%yourValue%';To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table SumDemo -> ( -> Words varchar(100), -> Counter int -> ); Query OK, 0 rows affected (0.93 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into SumDemo values('Are You There', 10); Query OK, 1 ... Read More

How to select data in MySQL where a field has a minimum value?

Arjun Thakur
Updated on 30-Jul-2019 22:30:24

9K+ Views

To select data where a field has min value, you can use aggregate function min(). The syntax is as follows.SELECT *FROM yourTableName WHERE yourColumnName=(SELECT MIN(yourColumnName) FROM yourTableName);To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table MinValueDemo -> ( -> ProductId int, -> ProductName varchar(100), -> ProductPrice int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into MinValueDemo values(1, 'product-1', 4500); Query OK, 1 row affected (0.14 sec) mysql> insert into MinValueDemo values(2, ... Read More

How to replace values of select return in MySQL?

George John
Updated on 30-Jul-2019 22:30:24

1K+ Views

You can use select case statement for this. The syntax is as follows.select yourColumnName1, yourColumnName2, ...N, case when yourColumnName=1 then 'true' else 'false' end as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table selectReturnDemo -> ( -> Id int, -> Name varchar(100), -> isGreaterthan18 tinyint(1) -> ); Query OK, 0 rows affected (0.62 sec)Now you can insert some records in the table using insert command. The query is as follows.mysql> insert into selectReturnDemo values(1, 'Carol', 0); Query OK, 1 row affected (0.23 sec) mysql> ... Read More

Does SQL Server have an equivalent to MySQL\\\'s ENUM data type?

Venu Madhavi
Updated on 22-Jan-2025 18:08:33

3K+ Views

No, SQL Server doesn’t offer a direct equivalent to MySQL’s ENUM data type, but you can replicate similar functionality with a combination of VARCHAR, and a CHECK constraint. This allows you to restrict the possible values for a column, just like ENUM does in MySQL. This article will look at how SQL Server can handle ENUM-like behavior and examples of how it is being utilized in your database design. Enum in MySQL In MySQL, the ENUM is a data type that is used to create a column with a fixed set of predefined values which allows data integrity. ... Read More

How can I add a Boolean field to MySQL?

Arjun Thakur
Updated on 30-Jul-2019 22:30:24

2K+ Views

You can use tinyint(1) or bool or boolean. All are synonym. If you use bool or boolean datatype, then it nternally change into tinyint(1).In PHP, the value 0 represents false and 1 represents true. Any other number except 0 is also true.Let us check the internal representation of bool or boolean using a table. The query to create a table is as follows.mysql> create table AddBoolDemo -> ( -> isToggle bool -> ); Query OK, 0 rows affected (1.24 sec)To check the DDL of the table, the following is the query.SHOW CREATE TABLE yourTableName;Let us check the representation of bool ... Read More

How to cut only the first character in MySQL string?

George John
Updated on 30-Jul-2019 22:30:24

4K+ Views

To cut only the first character, use the substr() function with UPDATE command. The syntax is as follows.UPDATE yourTableName set yourColumnName=substr(yourColumnName, 2);To understand the above syntax, let us first create a table. The query to create a table is as follows.mysql> create table CutStringDemo -> ( -> Value varchar(100) -> ); Query OK, 0 rows affected (0.66 sec)Now you can insert some records in the table using insert command. The query is as follows.mysql> insert into CutStringDemo values(', 12, 3456'); Query OK, 1 row affected (0.14 sec) mysql> insert into CutStringDemo values(', 23, 9867'); Query OK, 1 row affected ... Read More

Retrieve first 40 characters of a text field in MySQL?

Vrundesha Joshi
Updated on 30-Jul-2019 22:30:24

171 Views

To get the first 40 characters from a text field, use LEFT() function from MySQL. The syntax is as follows −SELECT LEFT(yourColumnName, 40) as anyVariableName from yourTableName;To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table retrieveFirst40Characters −> ( −> AllWords text −> ); Query OK, 0 rows affected (0.59 sec)Now you can insert some record in the table with the help of insert command. The query is as follows −mysql> insert into retrieveFirst40Characters values('This is a query demo ... Read More

Advertisements