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MySQLi Articles
Page 161 of 341
Create index of three columns in MySQL?
For index, you can use KEY(). Let us first create a −mysql> create table DemoTable1437 -> ( -> StudentId int, -> StudentName varchar(20), -> StudentMarks int, -> StudentAge int -> , -> KEY(StudentId, StudentMarks, StudentAge) -> ); Query OK, 0 rows affected (0.97 sec)Following is the query to check the description of −mysql> desc DemoTable1437;This will produce the following output −+--------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+-------+ | StudentId | int(11) | YES | MUL ...
Read MoreMySQL query to update different fields based on a condition?
Let us first create a −mysql> create table DemoTable1436 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (1.06 sec)Insert some records in the table using insert −mysql> insert into DemoTable1436(Name) values('Chris'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected (0.40 sec) mysql> insert into DemoTable1436(Name) values('Bob'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable1436(Name) values('David'); Query OK, 1 row affected ...
Read MoreOrder dates in MySQL with the format "01 August 2019"?
To display dates like “01 August 2019”, use ORDER BY STR_TO_DATE(). Let us first create a −mysql> create table DemoTable1435 -> ( -> DueDate varchar(60) -> ); Query OK, 0 rows affected (1.08 sec)Insert some records in the table using insert −mysql> insert into DemoTable1435 values('01 August 2019'); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable1435 values('01 Feb 2018'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1435 values('31 Jan 2017'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1435 values('01 March 2019'); Query OK, 1 row affected (0.11 sec)Display ...
Read MoreInsert current time minus 1 hour to already inserted date-time records in MYSQL
For subtracting dates, use MySQL DATE_SUB(). Let us first create a −mysql> create table DemoTable1434 -> ( -> ArrivalDatetime datetime -> ); Query OK, 0 rows affected (3.14 sec)Insert some records in the table using insert −mysql> insert into DemoTable1434 values('2019-09-30 21:10:00'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1434 values('2018-09-30 22:20:40'); Query OK, 1 row affected (0.33 sec) mysql> insert into DemoTable1434 values('2017-09-30 23:10:00'); Query OK, 1 row affected (0.19 sec)Display all records from the table using select −mysql> select * from DemoTable1434;This will produce the following output −+---------------------+ | ArrivalDatetime ...
Read MoreFetch specific rows from a MySQL table with duplicate column values (names)?
Let us first create a −mysql> create table DemoTable1431 -> ( -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeName varchar(20), -> EmployeeCountryName varchar(20) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert −mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Adam Smith', 'AUS'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Chris Brown', 'US'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('John Doe', 'UK'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1431(EmployeeName, EmployeeCountryName) values('Chris Brown', 'AUS'); Query ...
Read MoreAppend special characters to column values in MySQL
Let us first create a −mysql> create table DemoTable1626 -> ( -> Name varchar(20) -> ); Query OK, 0 rows affected (0.37 sec)Insert some records in the table using insert −mysql> insert into DemoTable1626 values('Chris'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1626 values('Bob'); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable1626 values('Robert'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select −mysql> select * from DemoTable1626;This will produce the following output −+--------+ | Name | +--------+ | Chris | | Bob | | ...
Read MoreSelect count of values (Yes, No) with same ids but different corresponding records in MySQL?
For this, you can use SUM() along with CASE statement. Let us first create a −mysql> create table DemoTable1430 -> ( -> EmployeeId int, -> isMarried ENUM('YES', 'NO') -> ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert −mysql> insert into DemoTable1430 values(1001, 'Yes'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1430 values(1001, 'No'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1430 values(1001, 'Yes'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1430 values(1001, 'Yes'); Query OK, 1 row affected (0.16 sec)Display ...
Read MoreFetch date records comparing with the current date's day and month in MySQL
For this, use MONTH() and DAY(). Let us first create a −mysql> create table DemoTable1429 -> ( -> AnniversaryDate date -> );Insert some records in the table using insert −mysql> insert into DemoTable1429 values('2019-09-29'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1429 values('2018-09-27'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1429 values('2016-09-28'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1429 values('2015-09-29'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select −mysql> select * from DemoTable1429;This will produce the following output −+-----------------+ | AnniversaryDate ...
Read MoreCount the number of comma's in every record from a comma-separated value column in MySQL
Let us first create a −mysql> create table DemoTable1510 -> ( -> Value varchar(50) -> ); Query OK, 0 rows affected (6.75 sec)Insert some records in the table using insert −mysql> insert into DemoTable1510 values('20, 35'); Query OK, 1 row affected (0.57 sec) mysql> insert into DemoTable1510 values('45, 67, 89'); Query OK, 1 row affected (0.99 sec) mysql> insert into DemoTable1510 values('90, 97, 101, 190'); Query OK, 1 row affected (1.15 sec)Display all records from the table using select −mysql> select * from DemoTable1510;This will produce the following output −+---------------+ | Value | ...
Read MoreFilter column value by the first character in MySQL
You can use LEFT() from MySQL. Let us first create a −mysql> create table DemoTable1428 -> ( -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeName varchar(20) -> ); Query OK, 0 rows affected (1.05 sec)Insert some records in the table using insert −mysql> insert into DemoTable1428(EmployeeName) values('Chris Brown'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1428(EmployeeName) values('Bob Brown'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1428(EmployeeName) values('John Smith'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable1428(EmployeeName) values('David Miller'); Query OK, 1 row affected (0.18 sec) ...
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