Found 4219 Articles for MySQLi

To store money amounts in MySQL, the best choice is to use DECIMAL data type or NUMERIC type. Float data type is not a good choice for money amounts. It gives some rounding errors. Therefore, avoid float for money amounts.Let us first create a table with data type DECIMAL. The following is the query to create a table −mysql> create table MoneyStorageDemo -> ( -> Amount DECIMAL(4, 2) -> ); Query OK, 0 rows affected (0.44 sec)Inserting some values into the table with the help of insert command. The query is ... Read More

You cannot do select IN range. For the same result, use BETWEEN. Let us see an example −IN(start, end): It means that the intermediate value between start and end won’t get displayed. For the above logic, you can use BETWEEN.BETWEEN clause is inclusive, for example, suppose there are 1, 2, 3, 4, 5, 6 numbers. If you want to display numbers from 2 to 6 inclusively, then using BETWEEN the numbers 2 and 6 will also get displayed.Let us create a table −mysql> create table SelectInWithBetweenDemo -> ( -> PortalId int ... Read More

To add AUTOINCREMENT in MySQL, you can use the ALTER command.ALTER TABLE yourTableName change yourColumName yourColumnName dataType AUTO_INCREMENT PRIMARY KEY;To understand the above concept, create a table with a column. Let us create a table −mysql> create table AlterTableToAddAutoIncrement -> ( -> StudentId int -> ); Query OK, 0 rows affected (0.57 sec)Implement the above syntax to change “StudentId” with AUTOINCREMENT. The query is as follows −mysql> alter table AlterTableToAddAutoIncrement change StudentId StudentId int AUTO_INCREMENT Primary key; Query OK, 0 rows affected (1.93 sec) Records: 0 Duplicates: 0 Warnings: 0We ... Read More

To know the biggest value from two or more fields, use the function GREATEST() from MySQL.The syntax is as follows −SELECT GREATEST(MAX(yourColumnName1), MAX(yourColumnName2), ...............MAX(yourColumnName2) ) from yourTableName;Let us understand the above concept by creating a table with more than two columns −mysql> create table GreatestOfTwoOrMore -> ( -> Marks1 int, -> Marks2 int, -> Marks3 int -> ); Query OK, 0 rows affected (0.57 sec)Here is the query to insert records in a table −mysql> insert into GreatestOfTwoOrMore values(23, 78, 89); Query OK, 1 row ... Read More

You can strip time component from datetime with the help of DATE() function. The syntax is as follows −SELECT DATE(yourColumnName) from yourTableName;To understand the above concept, let us first create a table −mysql> create table StripComponentDatetimeDemo -> ( -> YourDateTime datetime -> ); Query OK, 0 rows affected (0.60 sec)Let us now insert some records in the table. The query is as follows −mysql> insert into StripComponentDatetimeDemo values(date_add(now(), interval 1 day)); Query OK, 1 row affected (0.13 sec)Display records with the help of select statement. The query is as follows displaying ... Read More

To round down to nearest integer, use FLOOR() function from MySQL. The syntax is as follows −SELECT FLOOR(yourColumnName) from yourTableName;Let us first create a table −mysql> create table FloorDemo -> ( -> Price float -> ); Query OK, 0 rows affected (0.57 sec)Insert records to column Price. The query to insert records is as follows −mysql> insert into FloorDemo values(5.75); Query OK, 1 row affected (0.21 sec) mysql> insert into FloorDemo values(5.23); Query OK, 1 row affected (0.31 sec) mysql> insert into FloorDemo values(5.50); Query OK, 1 row affected (0.12 sec)Display ... Read More

To part DATE and TIME from DATETIME, you can use the DATE_FORMAT() method from MySQL. The syntax is as follows −SELECT DATE_FORMAT(yourColumnName, '%Y-%m-%d') VariableName, DATE_FORMAT(yourColumnName, '%H:%i:%s') VariableName from yourTableName;To understand the above method DATE_FORMAT(), let us create a table with data type “datetime”.Creating a table −mysql> create table DateAndTimePartDemo -> ( -> YourDateandtime datetime -> ); Query OK, 0 rows affected (0.56 sec)Now, I am inserting current date and time using now(). The query is as follows −mysql> insert into DateAndTimePartDemo values(now()); Query OK, 1 row affected (0.37 sec)Display the record ... Read More

To know a MySQL table is using MyISAM or InnoDB engine, you can use the command show status table. The syntax is as follows −SHOW TABLE STATUS from yourDatabaseName LIKE ‘yourTableName’.The above syntax tells about the specific table engine. Now you can apply the above syntax to know whether the MySQL table engine is using MyISAM or InnoDB.Here, I have database ‘business’ and table ‘student’. The query is as follows −mysql> show table status from business like 'student';The following displays the engine our table ‘student’ is using −+---------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+--------------------+----------+----------------+---------+ | Name   | Engine | Version | Row_format | Rows | ... Read More

To find my.cnf on Windows system, first open the command prompt with the help of shortcut key Windows + R (run). The snapshot is as follows −Type “services.msc” on command prompt and press ENTER as shown in the following screenshot −Now, a new wizard will open. The snapshot is as follows −Now, search for MySQL. The snapshot is as follows −Right click on “MySQL80” and select “Properties” as in the following screenshot −As you can see in the above screenshot, “Path to executable” tells about the location of my.cnf on Windows.

You can create user if it does not exist with the help of “create user” command. The command will work on MySQL version 5.7.6 and above. The syntax is as follows −mysql> CREATE USER IF NOT EXISTS 'yourUserName'@'localhost' IDENTIFIED BY 'yourPassword';Apply the above syntax to create a user if it does not exist. The query is as follows −mysql> CREATE USER IF NOT EXISTS 'Smith'@'localhost' IDENTIFIED BY 'Smith123456'; Query OK, 0 rows affected (0.29 sec)To check the new user is created or not, use the below query −mysql> SELECT User FROM mysql.user;The following is the output −+------------------+ | User ... Read More