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To count distinct values, you can use distinct in aggregate function count().The syntax is as follows −select count(distinct yourColumnName) as anyVariableName from yourTableName;To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table DistinctDemo −> ( −> Name varchar(200) −> ); Query OK, 0 rows affected (0.58 sec)For our example, let us insert duplicate records in the table. The query to insert records is as follows −mysql> insert into DistinctDemo values('John'); Query OK, 1 row affected (0.15 sec) mysql> ... Read More
The int is the synonym of integer in MySQL 5.0. Here is the demo display both int and integer internally represents int(11).Creating a table with int datatypemysql> create table IntDemo -> ( -> Id int -> ); Query OK, 0 rows affected (1.04 sec)Here is description of the table. The query is as followsmysql> desc IntDemo;The following is the output+-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | Id | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+-------+ 1 row in ... Read More
A smartphone is the most common device often seen in the hands of people, starting from the small kids to a 60 years old man. What is so special about this gadget? Does it only make life easier? What are the additional benefits this gadget offers? Numerous questions come to the mind of the users when they are buying the smart phone for the first time.For some folks, these gadgets are nothing but an instrument of entertainment. For some, it is the way to communicate to people around the world; some use it as the camera, whereas some may use ... Read More
To change the column in MySQL from int to double you need to use ALTER TABLE command.The syntax is as follows:ALTER TABLE yourTableName modify column yourColumnName DOUBLE NOT NULL;If you want NULL value then remove NOT NULL from the above syntax. The syntax is as follows:ALTER TABLE yourTableName modify column yourColumnName DOUBLE;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table IntToDoubleDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(10), -> CylinderVolume int, -> PRIMARY KEY(Id) -> ); Query OK, ... Read More
To implement GROUP BY on two fields and count, let us create a table. The following is the query to create a table −mysql> create table GroupByTwoFieldsDemo −> ( −> Id int, −> Name varchar(200) −> ); Query OK, 0 rows affected (0.53 sec)Let us insert some records in the table −mysql> insert into GroupByTwoFieldsDemo values(1, 'John'); Query OK, 1 row affected (0.15 sec) mysql> insert into GroupByTwoFieldsDemo values(10, 'Johnson'); Query OK, 1 row affected (0.16 sec) mysql> insert into GroupByTwoFieldsDemo values(9, 'Carol'); Query OK, 1 row affected (0.14 sec) mysql> insert into ... Read More
Here is a stored procedure that takes one parameter for input (IN) and second parameter for output (OUT)mysql> delimiter // mysql> create procedure Sp_SQRT(IN Number1 INT, OUT Number2 FLOAT) -> Begin -> set Number2=sqrt(Number1); -> end; -> // Query OK, 0 rows affected (0.24 sec) mysql> delimiter ;Call the stored procedure and send the value to the user variable. The syntax is as followsCALL yourStoredProcedureName(anyIntegerValue, @anyVariableName);Check what value is stored in the variable @anyVariableName. The syntax is as followsSELECT @anyVariableName;Created the stored procedure with the name ‘Sp_SQRT’. The ... Read More
You cannot update with regexp i.e. you need to use LIKE operator instead of regexp. MySQL does not provide support for update with regexp. The LIKE operator is as follows:UPDATE yourTableName SET yourColumnName= REPLACE(yourColumnName, yourValue)', '' ) WHERE yourColumnNameLIKE '%yourValueThatWillReplace)%';To understand the above syntax, let us create a table.mysql> create table Replace_Demo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Value varchar(20), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert into Replace_Demo(Value) values('221)'); Query OK, 1 ... Read More
To get dates older than 1 week, you can use the following syntax −select *from yourTableName where yourColumnName < now() - interval 1 week;To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table DatesOfOneWeek −> ( −> ArrivalTime datetime −> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table −mysql> insert into DatesOfOneWeek values(date_add(now(), interval 2 week)); Query OK, 1 row affected (0.11 sec) mysql> insert into DatesOfOneWeek values('2018-11-04'); Query OK, 1 row affected ... Read More
To validate email and phone in swift language we can use multiple conditional statements like if conditions, but that’s a long process and may contain 50-100s of if statements to validate email.So instead of conditionals we’ll use Regular expression. Swift provides NSPredicates which we can use to evaluate a regular expression and test them.Let’s see how we can use regular expressions to do the same.We’ll create a function which we can use as extension of String class or UIViewController to use through out the project.Add the following code to any class in your Project, or create a separate swift class ... Read More
You can truncate the text with ellipsis using LENGTH() with CASE statement. If your length is greater than 7 then truncate the text and add some number otherwise print the number as it is.To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table TruncateText -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Number longtext, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert into TruncateText(Number) values('64575868667687'); ... Read More