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Articles by Anvi Jain
Page 40 of 43
How to resolve the error that occurs while using a reserved word as a table or column name in MySQL?
This error occurs when you try to use a reserved word as a table or column name. It can occur due to −Case 1: Whenever you use reserved word as a table name −mysql> create table insert −> ( −> Id int −> );The error is as follows −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'insert ( Id int )' at line 1The above error occurred because the word ‘insert’ is a keyword in MySQL.Case 2 − Whenever you ...
Read MoreHow to Add Live Camera Preview to UIView in Swift?
To add a live camera preview to our default UIView in swift we can either use AVFoundation framework of iOS SDK or native UIImagePickerController(). In this example we’ll be using ImagePicker as our aim is to present camera preview on the UIView and Imagepicker is suitable for that task. AVFoundation can be used when we need a lot of customization on our camera or different types of custom actions.To show a camera preview on the UIView we need to perform the following steps.Create a UIImagePickerController object.Conform our class to UIImagePickerControllerDelegate and UINavigationControllerDelegate.Assign delegates to the object we created in step ...
Read MoreDelete more than one rows from a table using id in MySQL?
You can use IN statement to delete more than one rows from a table using id in MySQL. The syntax is as follows −delete from yourTableName where yourColumnName in(value1, value2, .....valueN);To understand the above syntax, let us create a table. The following is the query to create a table.mysql> create table DeleteManyRows −> ( −> Id int, −> Name varchar(200), −> Age int −> ); Query OK, 0 rows affected (3.35 sec)Insert some records in the table with the help of insert command. The query is as follows −mysql> insert into DeleteManyRows values(1, 'John', 23); ...
Read MoreMYSQL select DISTINCT values from two columns?
To select distinct values in two columns, you can use least() and greatest() function from MySQL.Let us create a table with two columns −mysql> create table SelectDistinctTwoColumns −> ( −> StudentId int, −> EmployeeId int −> ); Query OK, 0 rows affected (0.60 sec)Now you can insert records in the table. The query to insert records is as follows −mysql> insert into SelectDistinctTwoColumns values(100, 101); Query OK, 1 row affected (0.39 sec) mysql> insert into SelectDistinctTwoColumns values(102, 103); Query OK, 1 row affected (0.13 sec) mysql> insert into SelectDistinctTwoColumns values(104, 105); Query OK, 1 ...
Read MoreHow to make iPhone vibrate using Swift?
To make an iPhone vibrate using swift we’ll use two different methods. First create a new project and add Four different buttons to the main View controller.Now import the AudioToolbox framework in your view controller class.For the first button add an action and write the following code as shown below:@IBAction func actionButtonOne(_ sender: Any) { AudioServicesPlayAlertSound(SystemSoundID(kSystemSoundID_Vibrate)) }This will generate a long vibrating feedback on your device. Now to create more vibration effects on devices with iOS 10 or more we’ll add methods for all four different buttons.@IBAction func actionButtonTwo(_ sender: Any) { let generator = UIImpactFeedbackGenerator(style: .heavy) ...
Read MoreHow to open and close a PDF file using Swift?
In this article we’ll see how to open a pdf file using swift in iOS. Here we’ll do it with an example of opening pdf in webView in iOS. Let’s create a project and add WKWebView to the storyboard.Connect it’s outlet to the ViewController class.Now we’ll see two different thingsOpening a PDF file from a URL on the web.To open a web view from a url, first we need to have a url with a pdf file. In this example I’ll be using a dummy URL https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdfLet’s create a URL first, let url: URL! = URL(string: "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf")Now the remaining steps ...
Read MoreHow to query between two dates in MySQL?
You can query between dates with the help of BETWEEN statement. The syntax is as follows −select *from yourTableName where yourColumnName between ‘yourStartingDate’ and curdate().Use curdate() or now(), both these functions will work. To understand the above syntax, let us create a table −mysql> create table BetweenDateDemo −> ( −> StartDate datetime −> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table with the help of the following query −mysql> insert into BetweenDateDemo values(date_add(now(), interval -1 year)); Query OK, 1 row affected (0.11 sec) mysql> insert ...
Read MoreSetting similar value for a column in a MySQL table?
You can set value for a column of all records with the help of update command.The syntax is as follows if you want set NULL value for all the records in a column −update yourTableName set yourColumnName = NULL;Or if you want to use empty string, the following is the syntax −update yourTableName set yourColumnName = ’’;To understand the above concept, let us create a table. The query to create a table.mysql> create table StudentDemo −> ( −> Studentid int, −> StudentName varchar(100), −> Age int −> ); Query OK, 0 rows affected (0.64 sec)The ...
Read MoreHow to select an empty result set in MySQL?
Select an empty result set with the help of dummy table ‘dual’ from MySQL. The query is as follows −mysql> select 1 from dual where false; Empty set (0.00 sec)In the above query, “dual” is a dummy table and the above condition false. Therefore, it returns empty set.Let us check with true condition. It will return the selected value. The query is as follows −mysql> select 1 from dual where true;The following is the output −+---+ | 1 | +---+ | 1 | +---+ 1 row in set (0.00 sec)
Read MoreList of non-empty tables in all your MySQL databases?
To list non-empty tables in MySQL database, use “information_schema.tables”. The following is the query for all database tables −mysql> select table_type, table_name from information_schema.tables −> where table_rows >= 1;Above, we have considered only the table that have 1 or more than 1 rows i.e. non-empty table.The following is the output −+------------+------------------------------------------------------+ | TABLE_TYPE | TABLE_NAME | +------------+------------------------------------------------------+ | BASE TABLE | innodb_table_stats ...
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