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Database Articles
Page 241 of 547
Select 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 ...
Read MoreHow to Insert custom date into MySQL timestamp field?
The problem with UNIX_TIMESTAMP() function is that it returns an integer while we want to insert custom date i.e. not any integer part to MySQL date.Do not use UNIX_TIMESTAMP() for your column defined as TIMESTAMP because UNIX_TIMESTAMP() returns an integer.Check the UNIX_TIMESTAMP. The query is as follows −mysql> select UNIX_TIMESTAMP( '2019-01-09 15 −48 −23') AS IntegerValue;The following is the output −+--------------+ | IntegerValue | +--------------+ | 1547029103 | +--------------+ 1 row in set (0.00 sec)Look at the sample output, the UNIX_TIMESTAMP() function returns an integer of corresponding date and time.The syntax is as follows to insert custom date for ...
Read MoreMySQL - SELECT ... WHERE id IN (..) order with particular column?
You can SELECT ….WHERE id IN(..) using field() function to order with any column. The syntax is as follows −SELECT *FROM yourTableName WHERE yourColumnName IN(‘value1’, ’value2’, .......N) ORDER BY FIELD(yourColumnName, value1’, ’value2’, .......N);To understand the above syntax, let us create a table −mysql> create table SelectOrderbyField -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(30), -> Age int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SelectOrderbyField(Name, Age) values('John', 23); Query OK, ...
Read MoreMySQL Order By specific strings?
Order by the choice of strings you want, using the FIELD() function. The syntax is as follows −SELECT *FROM yourTableName ORDER BY FIELD(yourColumnName, ’yourValue1’, ’yourValue2’, ’yourValue3’, ....N);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table OrderByListOfStrings -> ( -> Id int not null auto_increment, -> CarName varchar(20), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into OrderByListOfStrings(CarName) values('Ford'); Query OK, 1 row affected ...
Read MoreHow to update two columns in a MySQL database?
You can update two columns using SET command separated with comma(, ). The syntax is as follows −UPDATE yourTableName SET yourColumnName1 = ’yourValue1’, yourColumnName2 = ’yourValue2’ where yourCondition;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table StudentInformations -> ( -> StudentId int not null auto_increment, -> StudentFirstName varchar(20), -> StudentLastName varchar(20), -> Primary Key(StudentId) -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into StudentInformations(StudentFirstName, StudentLastName) ...
Read MoreGet table column names in alphabetical order in MySQL?
To get the table column names in alphabetical order, you need to use ORDER BY. The syntax is as follows −SELECT anyReferenceName.COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS anyReferenceName WHERE anyReferenceName.TABLE_NAME = ’yourTableName’ ORDER BY anyReferenceName.COLUMN_NAMEFirst, we need to get all the columns and then we need to use ORDER BY. In the above query, we are getting all columns using INFORMATION_SCHEMA.COLUMNS.To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table ColumnsOrder -> ( -> StudentFirstName varchar(20), -> Id int, -> StudentAge int, -> StudentLastName varchar(20) ...
Read MoreFind max and second max salary for a MySQL Employee table?
You can get max and second max salary from an Employee table using LIMIT OFFSET. The syntax is as follows −SELECT yourColumnName1, yourColumnName2, ....N from yourTableName ORDER BY yourColumnName desc limit 2 offset 0;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table EmployeeMaxAndSecondMaxSalary -> ( -> EmployeeId int, -> Employeename varchar(20), -> EmployeeSalary int -> ); Query OK, 0 rows affected (0.88 sec)Insert some records in the table using insert command −mysql> insert into EmployeeMaxAndSecondMaxSalary values(1, 'John', 34566); Query OK, 1 row ...
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