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MySQLi Articles
Page 261 of 341
How to create a record in MySQL database subject to TTL (Time to live) option?
You need to use MySQL event scheduler. It manages the execution of events as well as scheduling.First, you need to create a table. After that you can create a event that will schedule every single day.Let us create a table. The query to create a table is as follows −mysql> create table EventDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EventDateTime datetime -> ); Query OK, 0 rows affected (0.71 sec)Now you can insert some records in the table using insert command. The query ...
Read MoreMySQL new user access denied even after giving privileges?
After creating a user and giving all privileges to the user, you need to FLUSH PRIVILEGES to set up and want the new settings to work correctly.The syntax is as follows −FLUSH PRIVILEGES;Here is the query to create a new user which has the name ‘Bob’ in my case. The query to create a new user is as follows −mysql> CREATE USER 'Bob'@'%' IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.56 sec)Now given all privileges to user Bob −mysql> GRANT ALL PRIVILEGES ON *.* TO 'Bob'@'%' WITH GRANT OPTION; Query OK, 0 rows affected (0.23 sec)Now flush the privileges. ...
Read MoreMySQL Merge selects together?
To merge selects together, you need to use GROUP BY clause. To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table MergingSelectDemo -> ( -> RoomServicesId int, -> RoomId int, -> ServiceId int -> ); Query OK, 0 rows affected (1.98 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into MergingSelectDemo values(10, 10, 10); Query OK, 1 row affected (0.29 sec) mysql> insert into MergingSelectDemo values(20, 10, 20); Query OK, 1 row affected ...
Read MoreROW_NUMBER() equivalent in MySQL for inserting?
There is no equivalent of ROW_NUMBER() in MySQL for inserting but you can achieve this with the help of variable. The syntax is as follows −SELECT (@yourVariableName:=@yourVariableName + 1) AS `anyAliasName`, yourColumnName1, yourColumnName2, ...N FROM yourTableName ,(SELECT @yourVariableName:=0) AS anyAliasName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table RowNumberDemo -> ( -> UserId int, -> UserName varchar(20) -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The ...
Read MoreSetting column values as column names in the MySQL query result?
To set column values as column names in the query result, you need to use a CASE statement.The syntax is as follows −select yourIdColumnName, max(case when (yourColumnName1='yourValue1') then yourColumnName2 else NULL end) as 'yourValue1', max(case when (yourColumnName1='yourValue2') then yourColumnName2 else NULL end) as 'yourValue2', max(case when yourColumnName1='yourValue3') then yourColumnName2 else NULL end) as 'yourValue3’, . . N from valueAsColumn group by yourIdColumnName order by yourIdColumnName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table valueAsColumn -> ( -> UserId int, -> UserColumn1 varchar(10), -> ...
Read MoreExact count of all rows in MySQL database?
To exactly count all rows, you need to use the aggregate function COUNT(*). The syntax is as follows −select count(*) as anyAliasName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table CountAllRowsDemo -> ( -> Id int, -> Name varchar(10), -> Age int -> ); Query OK, 0 rows affected (1.49 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into CountAllRowsDemo values(1, 'John', 23); Query OK, 1 row affected (0.15 ...
Read MorePerform search/replace for only the first occurrence of a character with session variable in MySQL
To perform search/ replace for only the first occurrence, use the CONCAT and REPLACE() function.The query is as follows to set user defined session variable −mysql> set @Sentence='Thks ks is a my string'; Query OK, 0 rows affected (0.00 sec)In this k will be replaced with i only once. The query is as follows. We have used INSTR() also −mysql> select @Sentence as NewString ,CONCAT(REPLACE(LEFT(@Sentence, INSTR(@Sentence, 'k')), 'k', 'i'), -> SUBSTRING(@Sentence, INSTR(@Sentence, 'k') + 1)) as ChangeOnlyOneTime;The following is the output displaying only the first occurrence of a character is replaced −+------------------------+------------------------+ | NewString ...
Read MoreHow to select part of a Timestamp in a MySQL Query?
To select part of a timestamp in a query, you need to use YEAR() function. The syntax is as follows in MySQL.select YEAR(yourTimestampColumnName) as anyAliasName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table SelectPartOfTimestampDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ShippingTime TIMESTAMP -> ); Query OK, 0 rows affected (1.11 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> ...
Read MoreHow to select all rows from a table except the last one in MySQL?
You need to use != operator along with subquery. The syntax is as follows −select *from yourTableName where yourIdColumnName != (select max(yourIdColumnName) from yourTableName );To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table AllRecordsExceptLastOne -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserName varchar(10), -> UserAge int -> , -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.65 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> ...
Read MoreResolve ERROR 1111 (HY000): Invalid use of group function in MySQL? How to correctly use aggregate function with where clause?
To correctly use aggregate function with where clause in MySQL, the following is the syntax −select *from yourTableName where yourColumnName > (select AVG(yourColumnName) from yourTableName);To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table EmployeeInformation -> ( -> EmployeeId int, -> EmployeeName varchar(20), -> EmployeeSalary int, -> EmployeeDateOfBirth datetime -> ); Query OK, 0 rows affected (1.08 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into EmployeeInformation values(101, 'John', 5510, '1995-01-21'); ...
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