If you want to get only digits using REGEXP, use the following regular expression( ^[0-9]*$) in where clause.Case 1 − If you want only those rows which have exactly 10 digits and all must be only digit, use the below regular expression.SELECT *FROM yourTableName WHERE yourColumnName REGEXP '^[0-9]{10}$';Case 2 − If you want only those rows with the digit either 1 or more, the following is the syntax −SELECT *FROM yourTableName WHERE yourColumnName REGEXP '^[0-9]*$';The above syntax will give only those rows that do not have any any characters.To understand the above syntax, let us create a table. The query ... Read More

Order by date and set the empty dates in the last with the help of ORDER BY clause and IS NULL property. The syntax is as follows:SELECT *FROM yourTableName ORDER BY (yourDateColumnName IS NULL), yourDateColumnName DESC;In the above syntax, we will sort the NULL first after that date. To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table DateColumnWithNullDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> LoginDateTime datetime, -> PRIMARY KEY(Id) -> ... Read More

The function TIME_TO_SEC() can be used in MySQL. If you want to convert datetime to seconds use the strtotime() from PHP. The MySQL syntax is as follows:SELECT TIME_TO_SEC(ABS(timediff(‘yourDateTimeValue’, now())));Now you can convert PHP datetime to seconds with the help of strtotime().First, you need to install XAMPP server to run your PHP program.After installing XAMPP successfully in C drive, here is the location wherein you need to include the PHP file. The snapshot is as follows:Note: Here, I have changed port of Apache to 8086 because default port was held by another program. This is done to begin running PHP program.Therefore, ... Read More

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 More

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 More

This error can occur if you try to set data higher than the allowed limit. As an example, you cannot store a string in a column of type bit because varchar or string takes size higher than bit data type.You need to use the following syntax for bit type column:anyBitColumnName= b ‘1’ OR anyBitColumnName= b ‘0’To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table IncasesensitiveDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(10),    -> PRIMARY KEY(Id)    -> ); Query OK, ... Read More

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 More

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 More

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 More

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 More