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Found 4219 Articles for MySQLi
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
442 Views
Following is the syntax to combine two fields in MySQL −alter table yourTableName add column yourColumnName dataType; update yourTableName set yourAddedColumnName =concat(yourColumnName1, ' ', yourColumnName2);Let us first create a table −mysql> create table DemoTable1590 -> ( -> FirstName varchar(20), -> LastName varchar(20) -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1590 values('Adam', 'Smith'); Query OK, 1 row affected (0.45 sec) mysql> insert into DemoTable1590 values('John', 'Doe'); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable1590 values('David', 'Miller'); Query OK, 1 row affected ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
325 Views
You cannot create database with numeric name as shown below −mysql> create database 1233;This will produce the following output −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1233' at line 1To create a database with numeric name, you need to use backticks around the database name −create database yourDatabaseName;Let us implement the above syntax −mysql> create database `1233`; Query OK, 1 row affected (0.20 sec)Now you can switch to the same database −mysql> use `1233`; Database changed
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
100 Views
For every single statement on MySQL command line, it shows the exact time to execute the specific statement.Let us first create a table −mysql> create table DemoTable1589 -> ( -> EmployeeId int, -> EmployeeName varchar(20) -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1589 values(101, 'Sam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1589 values(102, 'Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1589 values(103, 'David'); Query OK, 1 row affected (0.16 sec)Display all records from the table ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
461 Views
To select maximum of sum of two columns, use aggregate function MAX() along with subquery. Let us first create a table −mysql> create table DemoTable1587 -> ( -> Value1 int, -> Value2 int -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1587 values(30, 50); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1587 values(80, 90); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1587 values(40, 67); Query OK, 1 row affected (0.13 sec)Display all records from the table using select ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
85 Views
To display information about field names, the syntax is as follows −show columns from yourTableName;Let us first create a table −mysql> create table DemoTable1586 -> ( -> EmployeeId int, -> EmployeeFirstName varchar(20), -> EmployeeLastName varchar(20), -> EmployeeAge int, -> EmployeeCountryName varchar(20), -> EmployeeSalary int -> ); Query OK, 0 rows affected (0.78 sec)Following is the query to display field names −mysql> show columns from DemoTable1586;This will produce the following output −+---------------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
86 Views
An error will arise and nothing will get inserted in the table Let us see an example and create a table −mysql> create table DemoTable1585 -> ( -> StudentId int, -> StudentMarks int, -> UNIQUE(StudentId) -> ); Query OK, 0 rows affected (1.02 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1585 values(1,87),(2,98),(3,91),(3,48); ERROR 1062 (23000): Duplicate entry '3' for key 'StudentId'Display all records from the table using select statement −mysql> select * from DemoTable1585;This will produce the following output. Nothing gets inserted:Empty set (0.00 sec)
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
867 Views
Let us first create a table −mysql> create table DemoTable1584 -> ( -> DueDate datetime -> ); Query OK, 0 rows affected (1.79 sec)Here is the query to insert DATE in a MySQL −mysql> create trigger insertDate before insert on DemoTable1584 -> for each row set new.DueDate=curdate(); Query OK, 0 rows affected (0.22 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1584 values(); Query OK, 1 row affected (0.66 sec) mysql> insert into DemoTable1584 values(); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1584 values(); Query OK, 1 row affected ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
193 Views
To delete partial data, use UPDATE command along with REPLACE(). Let us first create a table −mysql> create table DemoTable1583 -> ( -> GameDetails text -> ); Query OK, 0 rows affected (1.38 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1583 values('=Candy, 2000'); Query OK, 1 row affected (0.53 sec) mysql> insert into DemoTable1583 values('=Lucky29, 10000'); Query OK, 1 row affected (0.25 sec)Display all records from the table using select statement −mysql> select * from DemoTable1583;This will produce the following output −+------------------------------------------------------------+ | GameDetails ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
110 Views
Let’s say the current date is −'2019-10-20We will first see an example and create a table −mysql> create table DemoTable1582 -> ( -> PostedDate datetime -> ); Query OK, 0 rows affected (13.36 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1582 values('2019-01-21 12:34:40'); Query OK, 1 row affected (1.06 sec) mysql> insert into DemoTable1582 values('2019-10-15 11:00:00'); Query OK, 1 row affected (0.87 sec) mysql> insert into DemoTable1582 values('2019-10-25 1:10:00'); Query OK, 1 row affected (1.14 sec)Display all records from the table using select statement −mysql> select * from DemoTable1582;This will produce the ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
348 Views
To ensure that MySQL rows are unique, you need to use UNIQUE constraint. Let us first create a table −mysql> create table DemoTable1580 -> ( -> id int, -> Name varchar(20), -> Age int -> ); Query OK, 0 rows affected (0.73 sec)Here is the query to create unique constraints to ensure MySQL rows are unique −mysql> alter table DemoTable1580 add unique index(id, Name, Age); Query OK, 0 rows affected (0.45 sec) Records: 0 Duplicates: 0 Warnings: 0Insert some records in the table using insert command −mysql> insert into DemoTable1580 values(101, 'Chris', 21); Query OK, ... Read More