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MySQL Articles
Page 339 of 355
How to implement WHILE LOOP with IF STATEMENT MySQL?
The following is an example to implement MySQL WHILE LOOP with IF statement. We are using in a stored procedureThe following is the query to create our stored procedure:mysql> DELIMITER // mysql> create procedure sp_getDaysDemo() -> BEGIN -> SELECT MONTH(CURDATE()) INTO @current_month; -> SELECT MONTHNAME(CURDATE()) INTO @current_monthname; -> SELECT DAY(LAST_DAY(CURDATE())) INTO @total_numberofdays; -> SELECT CAST(DATE_FORMAT(NOW() ,'%Y-%m-01') as DATE)INTO @check_weekday; -> SELECT DAY(@check_weekday) INTO @check_day; -> SET @count_days = 0; -> SET @workdays = 0; ...
Read MoreHow to find all uppercase strings in a MySQL table?
To find all upper case strings in a MySQL table, you need to use BINARY UPPER() function. The syntax is as follows:SELECT *FROM yourTableName WHERE yourColumnName=BINARY UPPER(yourColumnName);To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table FindUpperCaseDemo -> ( -> Id int, -> FirstName varchar(20), -> Age int -> ); Query OK, 0 rows affected (1.04 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert into FindUpperCaseDemo values(1, 'John', 23); Query OK, 1 row affected (0.17 sec) mysql> ...
Read MoreSELECT MySQL rows where today's date is between two DATE columns?
To select MySQL rows where today’s date is between two date columns, you need to use AND operator. The syntax is as follows:SELECT *FROM yourTableName WHERE yourDateColumnName1 = ‘’yourDateValue’;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table selectDates -> ( -> Id int NOT NULL AUTO_INCREMENT, -> StartingDate date, -> EndingDate date, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in ...
Read MoreDifference between two selects in MySQL?
You can use subqueries for difference between two selects in MySQL. The syntax is as follows:SELECT *FROM yourTableName where yourColumnName NOT IN(SELECT yourColumnName FROM youTableName WHERE yourCondition;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table DifferenceSelectDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserId int, -> UserValue int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert into DifferenceSelectDemo(UserId, UserValue) values(10, 10); Query ...
Read MoreMySQL convert timediff output to day, hour, minute, second format?
To understand the MySQL convert timediff output to day, hour, minute, and second format, you need to use CONCAT() from MySQL.Let us create a table. The query to create a table is as follows:mysql> create table convertTimeDifferenceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> StartDate datetime, -> EndDate datetime, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command. The query to insert record is as follows:mysql> insert into convertTimeDifferenceDemo(StartDate, ...
Read MoreSet MySQL DECIMAL with accuracy of 10 digits after the comma?
As you know the DECIMAL() method takes two parameter. The first parameter tells about the total number of digits and second parameter tells about number of digits after decimal point. Therefore, if you use DECIMAL(10, 10) that means you can use only 10 fractional digit.For Example: Store 0.9999999999 with DECIMAL(20, 10).To understand what we discussed above, let us create a table. The query to create a table is as follows:mysql> create table Decimal_Demo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Price DECIMAL(20, 10), -> PRIMARY KEY(Id) ...
Read MoreHow to find nth highest value of a MySQL column?
To find the nth highest value of a column, you need to use ORDER BY DESC with LIMIT clause. If you want the second highest value of a column, use the below syntax:SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 1, 1;If you want the fourth highest value of a column, use the below syntax:SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 3, 1;If you want the first highest value of a column, use the below syntax:SELECT *FROM yourTableName ORDER BY DESC yourColumnName LIMIT 1;As discussed in the above syntax, you need to change only in LIMIT clause. To understand ...
Read MoreHow to remove special characters from a database field in MySQL?
You can remove special characters from a database field using REPLACE() function. The special characters are double quotes (“ “), Number sign (#), dollar sign($), percent (%) etc.The syntax is as follows to remove special characters from a database field.UPDATE yourTableName SET yourColumnName=REPLACE(yourColumnName, ’yourSpecialCharacters’, ’’);To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table RemoveSpecialCharacterDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> PRIMARY Key(Id) -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using ...
Read MoreMySQL concat() to create column names to be used in a query?
To create column names to be used in a query, you need to use a user-defined variable with the set command. The syntax is as follows −SET @anyVariableName := ( SELECT CONCAT ( "SELECT", GROUP_CONCAT(CONCAT(" 1 as ", COLUMN_NAME) SEPARATOR ', '), " FROM DUAL") FROM INFORMATION_SCHEMA_COLUMNS WHERE TABLE_NAME= ‘yourTableName’ );Now prepare the statement using the PREPARE command. The syntax is as follows −PREPARE anyVariableName from @anyVariableName;Execute statement using EXECUTE command. The syntax is as follows −EXECUTE anyVariableName;Deallocate the prepared statement using DEALLOCATE command. The syntax is as follows −DEALLOCATE PREPARE anyVariableName; ...
Read MoreImprove MySQL Search Performance with wildcards (%%)?
No, MySQL won’t improve search performance whenever you have leading wildcards because MySQL will be unable to use the index. If you change to ‘anyLetter%’ then it will be able to use indexThe below syntax is better to use with trailing wildcards. The syntax is as follows −SELECT *FROM yourTableName WHERE yoorColumnName LIKE ‘anyLetter%’;The query to create a table is as follows −mysql> create table TrailingWildCardDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name Varchar(20), -> PRIMARY KEY(Id) -> ); Query OK, 0 ...
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