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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL order by string with numbers?
To MySQL order string with numbers, the following is the syntax, wherein we have used ORDER BY, SUBSTR() and CAST() −SELECT *FROM yourTableName ORDER BY SUBSTR(yourColumnName FROM 1 FOR 2), CAST(SUBSTR(yourColumnName FROM 2) AS UNSIGNED);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table OrderByStringWithNumbers -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Words varchar(10), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert ...
Read MoreHow can I update the boolean values in MySQL?
You can update boolean value using UPDATE command. If you use the BOOLEAN data type, MySQL internally convert it into tinyint(1). It can takes true or false literal in which true indicates 1 to tinyint(1) and false indicates 0 to tinyint(1).The syntax is as follows −UPDATE yourTableName SET yourColumnName = yourValue WHERE yourCondition;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table UpdateBooleans -> ( -> Id int NOT NULL AUTO_INCREMENT, -> isSuccessful BOOLEAN, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows ...
Read MoreCan we override final methods in Java?
Overriding is a one of the mechanisms to achieve polymorphism. This is the case when we have two classes where, one inherits the properties of another using the extends keyword and, these two classes same method including parameters and return type (say, sample).Since it is inheritance. If we instantiate the subclass a copy of superclass’s members is created in the subclass object and, thus both methods are available to the subclass.When we invoke this method (sample) JVM calls the respective method based on the object used to call the method.Overriding final methodsNo, you cannot override final method in java. If ...
Read MoreIs `definer` required when creating a MySQL stored procedure?
No, definer part is not compulsory when you are creating a stored procedure. It is used when you want to create a definer.Check all the user and host from the MySQL.user table −mysql> select user, host from mysql.user;The following is the output −+------------------+-----------+ | user | host | +------------------+-----------+ | Manish | % | | User2 | % | | mysql.infoschema | % | | mysql.session | % ...
Read MoreMySQL select * with distinct id?
You can use GROUP BY command for select with distinct id. The syntax is as follows −SELECT *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 DistinctIdDemo -> ( -> Id int, -> Name varchar(20), -> Age int -> ); Query OK, 0 rows affected (1.03 sec)Insert some records in the table using insert command. Here, we have added ID with duplicate values.The query is as follows −mysql> insert into DistinctIdDemo values(1, 'Mike', 23); Query OK, 1 row ...
Read MoreMySQL BETWEEN without the beginning and endpoints?
If you do not want to include start and end value in between, then use the following syntax −SELECT * FROM yourTableName WHERE yourColumnName BETWEEN yourStartingValue and yourEndingValue and yourColumnName not in (yourStartingValue , yourEndingValue );To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table BetweenWithoutEndPoints -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> Age int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.54 sec)Now you can insert some records in the table using ...
Read MoreSelect distinct combinations from two columns in MySQL?
To select distinct combinations from two columns, you can use CASE statement. Let us create a table with some columns.The query to create a table is as follows −mysql> create table select_DistinctTwoColumns -> ( -> Id int NOT NULL AUTO_INCREMENT, -> FirstValue char(1), -> SecondValue char(1), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.57 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into select_DistinctTwoColumns(FirstValue, SecondValue) values('s', 't'); Query OK, 1 row affected (0.12 sec) mysql> insert into select_DistinctTwoColumns(FirstValue, SecondValue) ...
Read MoreInsert sequential number in MySQL?
You can insert sequential number in MySQL using session variable. The syntax is as follows −SELECT @anyVariableName − = anyIntegerValue; UPDATE yourTableName SET yourColumnName = @anyVariableName − = @anyVariableName+IncrementStep;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table SequentialNumberDemo -> ( -> SequentialNumber int not null -> ); Query OK, 0 rows affected (0.84 sec)Insert records in the table using insert command. The query is as follows −mysql> insert into SequentialNumberDemo values(100); Query OK, 1 row affected (0.11 sec) mysql> insert into SequentialNumberDemo values(10); ...
Read MoreOrder by last 3 chars in MySQL?
You can use ORDER BY RIGHT() function to order by last 3 chars in MySQL. The syntax is as follows −SELECT *FROM yourTableName ORDER BY RIGHT(yourColumnName, 3) yourSortingOrder;Just replace the ‘yourSortingOrder’ to ASC or DESC to set the ascending or descending order respectively.To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table OrderByLast3Chars -> ( -> EmployeeId int NOT NULL AUTO_INCREMENT, -> EmployeeName varchar(20), -> EmployeeAge int, -> PRIMARY KEY(EmployeeId) -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in ...
Read MoreHow to add static value while INSERT INTO with SELECT in a MySQL query?
You can add static value when you use INSERT INTO SELECT MySQL query. Write the value directly in the select statement or you can add with the help of variable which initializes the value.Case 1 − Place the value directly in the INSERT INTO SELECT statement. The syntax is as follows −INSERT INTO yourSecondTableName(yourColumnName1, yourColumnName2, ....N) SELECT yourColumnName1 ,yourColumnName2, .....N, yourStaticValue from yourFirstTableName;Case 2 − Add using variable. The syntax is as follows −SET @yourVariableName − = yourstaticValue; INSERT INTO yourSecondTableName(yourColumnName1, yourColumnName2, ....N) SELECT yourColumnName1 ,yourColumnName2, .....N, @yourVariableName from yourFirstTableName;To understand the above syntax, you need to ...
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