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MySQLi Articles
Page 107 of 341
In MySQL, how to remove the specific prefix from entire column’s value and update them?
It can be done by applying TRIM() function on the column along with MySQL UPDATE statement. The example below will make it more clear.ExampleSuppose, we have a table ‘Employee’ which have the prefix ‘Dept.’ with all the values of Column ‘Department’ as follows −mysql> Select * from Employee; +------+----------------+------------+----------------------+ | Id | Name | Address | Department | +------+----------------+------------+----------------------+ | 100 | Raman | Delhi | IT Dept. | | 101 | Mohan ...
Read MoreWhy we cannot use comparison operator(=) for getting the rows with NULL from a table?
We cannot use = (comparison operator) because we know that NULL is not a value. If we want to get the rows with NULL from a table then we need to use IS NULL operator in MySQL query. Following example using the data from ‘employee’ table will exhibit it −Examplemysql> Select * from Employee WHERE Salary IS NULL; +----+-------+--------+ | ID | Name | Salary | +----+-------+--------+ | 7 | Aryan | NULL | | 8 | Vinay | NULL | +----+-------+--------+ 2 rows in set (0.00 sec)The query above use IS NULL operator and produces ...
Read MoreWhat happens if the position of insertion, in MySQL INSERT() function, is out of range?
MySQL INSERT() function performs no insertion if the position of insertion is out of range. The position of insertion can be out of range in the case when we pass a negative or 0(zero) value or the value goes beyond the value of a total number of characters in an original string by 2. It can be understood with the help of the following example −ExampleThe query below will perform no insertion because the position of insertion is out of range i.e. a negative value.mysql> Select INSERT('Virat', -1, 5, 'Kohli'); +-------------------------------+ | INSERT('Virat', -1, 5, 'Kohli') | +-------------------------------+ | Virat ...
Read MoreHow can I export values based on some conditions from MySQL table into a file?
We can use the conditions in WHERE clause while exporting the data from MySQL table to a file. It can be understood with the help of an example −ExampleSuppose we are having following data from table ‘Student_info’ −mysql> Select * from Student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 125 | Raman | Shimla | Computers | | 130 | Ram | Jhansi | ...
Read MoreWhat MySQL INSERT() function returns if the number of characters to be removed exceeds the number of characters available in original string?
In case if the number of characters to be removed exceeds the number of characters available in original string then MySQL INSERT() function will continue to remove the characters until the end of the original string.Examplemysql> Select INSERT('myteststring',3,15,'original'); +----------------------------------------+ | INSERT('myteststring',3,15,'original') | +----------------------------------------+ | myoriginal | +----------------------------------------+ 1 row in set (0.00 sec)
Read MoreHow can we use MySQL LPAD() and RPAD() functions in the same query for padding the string to both sides, left and right, of the original string?
For achieving this, we must have to use one of the functions as the 1st argument of the other function. In other words, either RPAD() function would be the 1st argument of LPAD() function or LPAD() function would be the 1st argument of RPAD() function. It can be understood with the help of the following exampleExamplemysql> Select RPAD(LPAD(' My name is Ram ', 23, '* '), 30, '* '); +------------------------------------------------+ | RPAD(LPAD(' My name is Ram ', 23, '* '), 30, '* ') | +------------------------------------------------+ | * * * * My name is Ram * * * * ...
Read MoreWhat MySQL returns if we provide an empty string for padding with other string in LPAD() or RPAD() functions?
Suppose if we provide an empty string for padding on LPAD() or RPAD() functions then MySQL will return NULL as output. Following example will demonstrate it −Examplemysql> Select LPAD('ABCD',22,''); +--------------------+ | LPAD('ABCD',22,'') | +--------------------+ | NULL | +--------------------+ 1 row in set (0.00 sec) mysql> Select RPAD('ABCD',22,''); +--------------------+ | RPAD('ABCD',22,'') | +--------------------+ | NULL | +--------------------+ 1 row in set (0.00 sec)
Read MoreHow MySQL evaluates the blank line between two lines written in the text file while importing that text file into MySQL table?
Suppose if there is a blank line between two line written in the text file then MySQL evaluates it as the data line while importing that text file into MySQL table. It can be understood with the help of the following example −ExampleSuppose we are having a blank line between two lines in a text file named ‘A.txt’ as follows −105, Chum, USA, 11000 106, Danny, AUS, 12000Now we can write the following query to import the data from text file into MySQL table −mysql> LOAD DATA LOCAL INFILE 'd:\A.txt' INTO table employee10_tbl FIELDS TERMINATED BY ', '; Query OK, ...
Read MoreHow to insert new string within a string subsequent to removing the characters from the original string by using MySQL function?
We can use MySQL INSERT() function to insert new string within a string after removing the characters from the original string.SyntaxINSERT(original_string, @pos, @len, new_string)Here, original_string is the string in which we want to insert new string at the place of some specific number of characters.@pos is the position at which the insertion of new string should start.@len is the number of characters should delete from the original string. The starting point of deletion of characters is value of @pos.New_string is the string we want to insert into the original string.Examplemysql> Select INSERT('Yash Sharma', 5, 7, ' Pal'); +----------------------------------+ | ...
Read MoreHow can we upload the changed value, rather than written in a text file, of column(s) while importing that text file into MySQL table?
Suppose if we want to upload the changed value rather than the value written in a text file then we need to use user variables along with the SET command. It can be understood with the help of the following example −ExampleSuppose we are having the following data in ‘A.txt’ −105, Chum, USA, 11000 106, Danny, AUS, 12000But we want to upload the value of salary after adding 500 to it at the time of importing it without changing the value of salary in a text file then it can be done with the help of the following query by ...
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