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Articles by AmitDiwan
Page 836 of 840
Select a value from MySQL database only if it exists only once from a column with duplicate and non-duplicate values
Let us first create a table −mysql> create table DemoTable723 (Value int); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable723 values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable723 values(200); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable723 values(200); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable723 values(100); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable723 values(300); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable723 values(400); Query OK, 1 row affected (0.16 sec) mysql> ...
Read MoreREGEX in MySQL to display only numbers separated by hyphen.
Let us first create a table −mysql> create table DemoTable ( Code varchar(100) ); Query OK, 0 rows affected (1.16 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('100-677-9876'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('100-677-9876-John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('David-100-677-9876'); Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------------------+ | Code | +--------------------+ ...
Read MoreIs there a way to list all the reserved words in MySQL using the MySQL command-line utility?
Yes, we can all the reserved words in MySQL using the command-line utility. Following is the syntax −select *from mysql.help_keyword;Let us implement the above syntax in order to get list of all the reserved words in MySQL.Following is the query −mysql> select *from mysql.help_keyword;This will produce the following output -
Read MoreDELETE from MySQL table WHERE column equals value AND column2 equals value2?
Let us first create a table −mysql> create table DemoTable722 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(100), StudentAge int ); Query OK, 0 rows affected (1.84 sec)Insert some records in the table using insert command −mysql> insert into DemoTable722(StudentName, StudentAge) values('Chris Brown', 23) ; Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable722(StudentName, StudentAge) values('John Smith', 21); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable722(StudentName, StudentAge) values('David Miller', 22); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable722(StudentName, StudentAge) values('Adam Smith', 20); Query OK, 1 row affected ...
Read MoreIs there such thing as a SELECT with an IF/ELSE statement in MySQL?
Yes, SELECT with an IF/ELSE is possible in MySQL.Let us first create a table −mysql> create table DemoTable721 ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(100), Marks int, CountryName varchar(100) ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable721(FirstName, Marks, CountryName) values('Chris', 56, 'US'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable721(FirstName, Marks, CountryName) values('Robert', 78, 'UK'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable721(FirstName, Marks, CountryName) values('Mike', 45, 'AUS'); Query OK, 1 row affected (0.16 sec) ...
Read MorePrevent having a zero value in a MySQL field?
Use trigger BEFORE INSERT on the table to prevent having a zero value in a MySQL field. Let us first create a table −mysql> create table DemoTable(Value int); Query OK, 0 rows affected (0.85 sec)Let us create a trigger to prevent having a zero value in a MySQL field −mysql> DELIMITER // mysql> create trigger preventing_to_insert_zero_value before insert on DemoTable for each row begin if(new.Value = 0) then SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'You can not provide 0 value'; END if; end // Query OK, 0 rows affected (0.34 sec) mysql> DELIMITER ...
Read MoreI used 'from' and 'to' with backticks as column titles in my database table. Now, how do I SELECT them?
At first, to use reserved words, it should be set with backticks like −`from` `to`Since you want to select the column names set with backtick as shown above, you need to implement the following −select `to`, `from` from yourTableName;Let us first create a table with column names as from and to with backticks −mysql> create table DemoTable720 ( `from` date, `to` date ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable720 values('2019-01-21', '2019-07-23'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable720 values('2017-11-01', '2018-01-31'); Query ...
Read MoreWhat does the slash mean in a MySQL query?
The slash means division ( /) in MySQL query. This can be used to divide two numbers. Here, we will see an example to divide numbers from two columns and display result in a new column.Let us first create a table −mysql> create table DemoTable719 ( FirstNumber int, SecondNumber int ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable719 values(20, 10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable719 values(500, 50); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable719 values(400, 20); ...
Read MoreHow to find all records which are NOT in the set array with MySQL?
For this, you can use NOT IN() function.Let us first create a table −mysql> create table DemoTable718 ( Id int, FirstName varchar(100), Age int ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable718 values(101, 'Chris', 26); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable718 values(102, 'Robert', 24); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable718 values(103, 'David', 27); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable718 values(104, 'Mike', 28); Query OK, 1 row affected (0.19 sec) mysql> ...
Read MoreIs it possible to sort varchar data in ascending order that have both string and number values with MySQL?
For this, you can use ORDER BY IF(CAST()). Let us first create a table −mysql> create table DemoTable(EmployeeCode varchar(100)); Query OK, 0 rows affected (1.17 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('190'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('100'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('120'); Query OK, 1 row affected (0.21 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------------+ ...
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