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MySQL Articles
Page 282 of 355
How to select ID column as null in MySQL?
Let us first create a table. The query to create a table is as followsmysql> create table selectAllDemo - > ( - > Name varchar(100), - > Age int - > ); Query OK, 0 rows affected (1.90 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into selectAllDemo values('John', 25); Query OK, 1 row affected (0.99 sec) mysql> insert into selectAllDemo values('Carol', 26); Query OK, 1 row affected (0.42 sec) mysql> insert into selectAllDemo values('Bob', 30); Query OK, 1 row affected (1.57 ...
Read MoreIs it possible to calculate a correlation in a MySQL query?
Yes, it is possible to calculate a correlation in a query. To understand the correlation in a query, you need to first create a table. The query to create a table is as followsmysql> create table correlationDemo - > ( - > value float not null, - > value2 float not null - > ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table with the help of insert command. The query is as follows to insert records in the tablemysql> insert into correlationDemo values(1, ...
Read MoreBest way to change the date format in MySQL SELECT?
The best way to change the date format in MySQL SELECT is as followsSELECT DATE_FORMAT(yourColumnName, "%d/%m/%Y %H:%i") AS anyAliasName FROM yourTableName WHERE yourCondition;To understand the above concept, let us create a table. The query to create a table is as followsmysql> create table bestDateFormatDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > ArrivalDateTime datetime - > ); Query OK, 0 rows affected (0.64 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into bestDateFormatDemo(ArrivalDateTime) values(now()); Query OK, ...
Read MoreHow to find the previous and next record using a single query in MySQL?
You can use UNION to get the previous and next record in MySQL.The syntax is as follows(select *from yourTableName WHERE yourIdColumnName > yourValue ORDER BY yourIdColumnName ASC LIMIT 1) UNION (select *from yourTableName WHERE yourIdColumnName < yourValue ORDER BY yourIdColumnName DESC LIMIT 1);To understand the concept, let us create a table. The query to create a table is as followsmysql> create table previousAndNextRecordDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Name varchar(30) - > ); Query OK, 0 rows affected (1.04 ...
Read MoreSelect text after last slash in MySQL?
You need to use substring_index() function from MySQL to select text.The syntax is as followsSELECT substring_index(yourColumnName, '/', -1) AS anyAliasName FROM yourTableName;To understand the above concept, let us create a table. The query to create a table is as followsmysql> create table selectTextAfterLastSlashDemo - > ( - > UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > UserPathDirectory varchar(200) - > ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into selectTextAfterLastSlashDemo(UserPathDirectory) values('C:/MyFolder1/MyEntityFramework'); Query OK, 1 ...
Read MoreRename Root @ localhost username in MySQL?
The syntax is as follows to rename Root @localhostUPDATE MySQL.user SET user = ‘yourNewRootName’ WHERE user = 'root';To understand the above concept, let us check all the user names and host. The query is as followsmysql> select user, host from MySQL.user;The following is the output+------------------+-----------+ | user | host | +------------------+-----------+ | Bob | % | | Manish | % | | User2 | % ...
Read MoreHow to move data between two tables with columns in different MySQL databases?
For this, you need to use an INSERT SELECT statement. The syntax is as followsINSERT INTO yourDatabaseName1.yourTableName1(yourColumnName1, yourColumnName2, ....N) SELECT yourColumnName1, yourColumnName2, ....N FROM yourdatabaseName2.yourTableName2;Here, I am using the following two databasessampletestLet us create the first table in the “test” databasemysql> use test; Database changed mysql> create table send -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (1.19 sec)Insert some records in the first table using insert command. The query is as followsmysql> insert into send(Name) values('John'); Query OK, 1 row affected ...
Read MoreDoes MySQL have an expanded output flag similar PostgreSQL?
Yes, you can get expanded out in MySQL using the /G, instead of semicolon(;). The syntax is as followsSELECT *FROM yourTableName\GLet us first create a table as an examplemysql> create table expandedOutputDemo - > ( - > EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > EmployeeName varchar(20), - > EmployeeAge int - > ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into expandedOutputDemo(EmployeeName, EmployeeAge) values('Larry', 27); Query OK, 1 row affected (0.16 sec) mysql> insert into expandedOutputDemo(EmployeeName, EmployeeAge) values('Mike', 29); Query ...
Read MoreCreate a new user with password in MySQL 8?
You need to use CREATE command to create a new user with password in MySQL 8. Let us check the versionmysql> select version(); +-----------+ | version() | +-----------+ | 8.0.12 | +-----------+ 1 row in set (0.14 sec)The syntax is as follows to create a new user with passwordCREATE USER 'yourUserName'@'localhost' IDENTIFIED BY 'yourPassword';The following is the syntax to grant all privileges to the created userGRANT ALL ON *.* TO 'yourUserName'@'localhost';Now flush the privileges using flush commandflush privileges; Let us create a new user with the help of the above syntax. The query is as followsmysql> use MySQL; Database ...
Read MoreHow to use actual row count (COUNT(*)) in WHERE clause without writing the same query as subquery in MySql?
Achieve this with the help of where clause.The syntax is as followsSELECT yourColumnName1, yourColumnName2, ...N FROM yourTableName WHERE ( SELECT COUNT(*) FROM yourTableName )=2;To understand the concept, let us create a table. The query to create a table is as followsmysql> create table CountWithSubqueryDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > EmployeeName varchar(20) - > ); Query OK, 0 rows affected (2.09 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into CountWithSubqueryDemo(EmployeeName) values('John'); Query OK, 1 row affected (0.54 sec) mysql> ...
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