Change Column Name from studentname to firstname in MySQL

karthikeya Boyini
Updated on 30-Jun-2020 14:27:02

189 Views

Use CHANGE with ALTER statement. Let us first create a table −mysql> create table DemoTable -> ( -> StudentName varchar(100), -> Age int -> ); Query OK, 0 rows affected (0.84 sec)Now check the description of table −mysql> desc DemoTable;OutputThis will produce the following output −+----------------+--------------+------+-----+---------+-------+ | Field          | Type         | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+-------+ | StudentName    | varchar(100) | YES | | NULL | | | Age         ... Read More

Fix DROP TABLE VIEW Hash1051 Unknown Table Error in MySQL

karthikeya Boyini
Updated on 30-Jun-2020 14:23:40

2K+ Views

To correctly drop a view, use the below syntax −drop view yourViewName;Let us first create a table −mysql> create table DemoTable -> ( -> Id int -> ); Query OK, 0 rows affected (1.01 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1001); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(1002); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values(1003); Query OK, 1 row affected (0.26 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+------+ | ... Read More

Find and Display Duplicate Values Only Once from a Column in MySQL

Sharon Christine
Updated on 30-Jun-2020 14:21:28

757 Views

Let us first create a table −mysql> create table DemoTable -> ( -> value int -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.24 sec) mysql> insert into ... Read More

Truncate a Table and Add Indexes in SQL

Sharon Christine
Updated on 30-Jun-2020 14:19:51

827 Views

If you truncate a table, you do not need to add indexes because table is recreated after truncating a table and indexes get added automatically.Let us first create a table −mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> FirstName varchar(20),    -> LastName varchar(20)    -> ); Query OK, 0 rows affected (0.65 sec)Following is the query to create an index −mysql> create index Index_firstName_LastName on DemoTable(FirstName, LastName); Query OK, 0 rows affected (1.04 sec) Records: 0 Duplicates: 0 Warnings: 0Insert some records in the table using insert command −mysql> ... Read More

MySQL Query to Return Substring After Delimiter

Sharon Christine
Updated on 30-Jun-2020 14:18:32

928 Views

Use SUBSTRING() to return values after delimiter. Let us first create a table −mysql> create table DemoTable -> ( -> Title text -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John is good in MySQL, Sam is good in MongoDB, Mike is good in Java'); Query OK, 1 row affected (0.19 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+-------------------------------------------------------------------+ | Title ... Read More

Usage of Zerofill in a MySQL Field

karthikeya Boyini
Updated on 30-Jun-2020 14:17:39

914 Views

Zerofill pads the displayed value of the field with zeros up to the display width specified in the column definition. For example, if column is set int(8), therefore the width is 8. If the number is let’s say 4376, then zero will be padded on the left for total width i.e. 8 −00004376Let us first create a table −mysql> create table DemoTable -> ( -> Number int(8) zerofill -> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.16 sec) mysql> insert ... Read More

MySQL Query to Search for a Specific Last Name

karthikeya Boyini
Updated on 30-Jun-2020 14:17:00

174 Views

You can use LIKE operator to conduct a basic search for last name. Let us first create a table: −mysql> create table DemoTable    -> (    -> CustomerName varchar(100),    -> CustomerAge int    -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John Doe', 34); Query OK, 1 row affected (1.32 sec) mysql> insert into DemoTable values('David Miller', 24); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Bob Doe', 27); Query OK, 1 row affected (0.18 sec) mysql> insert into ... Read More

Fetch Current Date Records in MySQL Using NOW() Function

karthikeya Boyini
Updated on 30-Jun-2020 14:15:35

423 Views

Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ShippingDate datetime -> ); Query OK, 0 rows affected (1.16 sec)Insert some records in the table using insert command. Consider current date “2019-06-28” −mysql> insert into DemoTable(ShippingDate) values('2019-01-31'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(ShippingDate) values('2019-06-06'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(ShippingDate) values('2019-06-28'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(ShippingDate) values('2019-07-01'); Query OK, 1 row affected (0.16 sec)Display all records from the table ... Read More

Selecting Data from MySQL Table Based on Specific Month

Sharon Christine
Updated on 30-Jun-2020 14:14:30

265 Views

Use the MONTH() method in MySQL to select date based on month. Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(10), -> UserPostMessageDate datetime, -> UserLikes int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName, UserPostMessageDate, UserLikes) values('John', '2019-01-31', 4560); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(UserName, UserPostMessageDate, UserLikes) values('Sam', '2019-06-28', 790); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable(UserName, UserPostMessageDate, UserLikes) values('Carol', '2019-05-01', ... Read More

Use contains() in Android LinkedBlockingDeque

Samual Sam
Updated on 30-Jun-2020 14:13:06

136 Views

Before getting into example, we should know what LinkedBlockingDeque is. It is implemented by Collection interface and the AbstractQueue class. It provides optional boundaries based on linked nodes.It going to pass memory size to constructor and helps to provide memory wastage in android.This example demonstrate about How to use contains() in android LinkedBlockingDequeStep 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 taken text view to show ... Read More

Advertisements