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Articles by Chandu yadav
Page 74 of 81
Selecting a single row in MySQL?
If you want to select a single row on the basis of primary key, use the WHERE clause. The syntax is as follows −SELECT * FROM yourTableName WHERE yourPrimaryKeyColumnName = someValue;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectWithPrimaryKey -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> Age int, -> Marks int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command. The query is ...
Read MoreSort by date & time in descending order in MySQL?
Let us create a table to sort date and time in ascending order. The query to create a table is as follows −mysql> create table SortByDateAndTime -> ( -> UserId int, -> UserName varchar(100), -> IssueDate date, -> IssueTime time -> ); Query OK, 0 rows affected (0.60 sec)Insert the records in the table using insert command. The query is as follows −mysql> insert into SortByDateAndTime values(1, 'John', '2018-12-16', '10:30'); Query OK, 1 row affected (0.14 sec) mysql> insert into SortByDateAndTime values(2, 'Bob', '2018-12-16', '10:10'); Query OK, 1 row affected (0.14 sec) ...
Read MoreEasy way to re-order columns in MySQL?
To re-order columns in MySQL, use the ALTER TABLE MODIFY COLUMN. The syntax is as follows -ALTER TABLE yourTableName MODIFY COLUMN yourColumnName data type after yourColumnName.To understand the above syntax, let us first create a table. The query to create a table is as follows.mysql> create table reOrderColumn -> ( -> ProductId int, -> DeliveryDate datetime, -> ProductName varchar(100) -> ); Query OK, 0 rows affected (0.76 sec)Now check the description of the table. The query is as follows.mysql> desc reOrderColumn;The following is the output.+--------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ...
Read MoreOrder a MySQL table by two columns?
Order a MySQL table by two columns with the help of below syntax −order by yourColumnName1 DESC, yourColumnName2 DESC;Let us first create a table for our example −mysql> create table OrderByDemo -> ( -> StudentId int, -> StudentName varchar(100), -> StudentAge int -> ); Query OK, 0 rows affected (0.57 sec)Inserting records into the table with the help of insert command. The query is as follows −mysql> insert into OrderByDemo values(1, 'John', 23); Query OK, 1 row affected (0.20 sec) mysql> insert into OrderByDemo values(3, ...
Read MoreHow to build a Horizontal ListView with RecyclerView in Android?
Before getting into example, we should know what is Recycler view in android. Recycler view is more advanced version of list view and it works based on View holder design pattern. Using recycler view we can show grids and list of items.This example demonstrate about how to build a horizontal list view with Recycler View by creating a beautiful student records app that displays student name with age.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Open build.gradle and add Recycler ...
Read MoreHow to implement Android Pull-to-Refresh?
Before getting into example, we should know what is Pull to refresh layout in android . we can call pull to refresh in android as swipe-to-refresh. when you swipe screen from top to bottom it will do some action based on setOnRefreshListener.This example demonstrate about how to implement android pull to refresh.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code we have given swipeRefreshLayout as parent ...
Read MoreHow to implement Android TextInputLayout
Before getting into example, we should know what is TextInputLayout in android. TextInputLayout is extended by Linear Layout. It going to act as a wrapper for edit text and shows flatting hint animation for edit text.This example demonstrate about how to implement Android TextInputLayout.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code ...
Read MoreCount number of rows in each table in MySQL?
To get the count of rows, you need to use information_schema.tables. The syntax is as follows.SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = ‘yourDatabaseName’;Let us implement the above syntax for a database with the name ‘test’. The query is as follows displaying the table names with the count of rows in the table.mysql> SELECT table_name, table_rows -> FROM INFORMATION_SCHEMA.TABLES -> WHERE TABLE_SCHEMA = 'test';The following is the output.+------------------------------------+------------+ | TABLE_NAME | TABLE_ROWS | +------------------------------------+------------+ | _student_trackerdemo | 0 | | _studenttrackerdemo | 0 | | add30minutesdemo | 0 | | addcolumn | 0 | ...
Read MoreMySQL Select to get users who have logged in today?
To get the users logged in today, use the below syntax. Here, we are expecting that your datetime field is a string type −select yourColumnName1, yourColumnName2, yourColumnName3, ...N from youTableName WHERE STR_TO_DATE(yourColumnName1, ‘format’') =CURDATE();Let’s say we have the following “DateEqualToday “ table that stores users first and last name with the login date −+------+------------+-----------+------------+ | Id | First_Name | Last_Name | LoginDate | +------+------------+-----------+------------+ | 1 | James | Smith | 20-12-2018 | | 2 | Carol | Taylor | 21-12-2017 | | 3 | John ...
Read MoreUsing single quotes around database and table name isn't working in MySQL?
You need to use backticks around table name as well as database name. The syntax is as follows:UPDATE `yourDatabaseName`.`yourTableName` SET yourColumnName1=yourColumnName1+1 WHERE yourColumnName2=’yourValue’;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> use test; Database changed mysql> create table Add1Demo -> ( -> Id varchar(10), -> Value int -> ); Query OK, 0 rows affected (1.19 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert into Add1Demo values('1', 780); Query OK, 1 row affected (0.17 sec) mysql> insert into Add1Demo values('2', ...
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