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Articles by karthikeya Boyini
Page 132 of 143
MySQL query to skip the duplicate and select only one from the duplicated values
The syntax is as follows to skip the duplicate value and select only one from the duplicated values −select min(yourColumnName1), yourColumnName2 from yourTableName group by yourColumnName2;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table doNotSelectDuplicateValuesDemo -> ( -> User_Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> User_Name varchar(20) -> ); Query OK, 0 rows affected (0.78 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into doNotSelectDuplicateValuesDemo(User_Name) values('John'); Query OK, 1 row affected ...
Read MoreAdd a value to Septet class in JavaTuples
The addAtX() method is used to add value to the Septet Tuple. The index can be set here with the X i.e. the place where the value gets added.Let us first see what we need to work with JavaTuples. To work with Septet class in JavaTuples, you need to import the following package −import org.javatuples.Septet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Septet Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example ...
Read MoreDisplay IDs in a particular order with MySQL IN()?
To display IDs in a particular order i.e. the order of your choice use FIELD() method.Let us first create a table −mysql> create table DemoTable ( UserId int ); Query OK, 0 rows affected (0.64 sec)Following is the query to insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(80); Query OK, 1 row affected (0.13 sec) ...
Read MoreHow to trim commas with MySQL?
The syntax is as follows to trim commas −SELECT TRIM(BOTH ', ' FROM yourColumnName) from yourTableName;Let us see an example −mysql> create table TrimCommasDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> AllTechnicalSkills text -> ); Query OK, 0 rows affected (0.81 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into TrimCommasDemo(AllTechnicalSkills) values(', C, C++, Java, '); Query OK, 1 row affected (0.14 sec) mysql> insert into TrimCommasDemo(AllTechnicalSkills) values(', MySQL, SQL Server, MongoDB, '); Query OK, 1 row affected (0.13 sec) mysql> ...
Read MorePerform search/replace for only the first occurrence of a character with session variable in MySQL
To perform search/ replace for only the first occurrence, use the CONCAT and REPLACE() function.The query is as follows to set user defined session variable −mysql> set @Sentence='Thks ks is a my string'; Query OK, 0 rows affected (0.00 sec)In this k will be replaced with i only once. The query is as follows. We have used INSTR() also −mysql> select @Sentence as NewString ,CONCAT(REPLACE(LEFT(@Sentence, INSTR(@Sentence, 'k')), 'k', 'i'), -> SUBSTRING(@Sentence, INSTR(@Sentence, 'k') + 1)) as ChangeOnlyOneTime;The following is the output displaying only the first occurrence of a character is replaced −+------------------------+------------------------+ | NewString ...
Read MoreSelect current time with MySQL now() and convert it to GMT 0?
You can use utc_timestamp() for this. Following is the syntax −SELECT utc_timestamp();Let us check the current time using now().Following is the query −mysql> select now();This will produce the following output −+---------------------+ | now() | +---------------------+ | 2019-04-11 17:50:05 | +---------------------+ 1 row in set (0.00 sec)Following is the query to get GMT 0 −mysql> SELECT utc_timestamp();This will produce the following output −+---------------------+ | utc_timestamp() | +---------------------+ | 2019-04-11 12:20:08 | +---------------------+ 1 row in set (0.00 sec)
Read MoreCreate Septet Tuple from another collection in Java
The fromCollection() method is used in JavaTuples to create Septet Tuple from another collection. We will see an example of creating a Septet Tuple using List collection.Let us first see what we need to work with JavaTuples. To work with Septet class in JavaTuples, you need to import the following package −import org.javatuples.Septet;Note − Steps to download and run JavaTuples program. If you are using Eclipse IDE to run Septet Class in JavaTuples, then Right Click Project ->Properties ->Java Build Path ->Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Septet; import java.util.*; public ...
Read MoreMySQL add "prefix" to every column?
To create a view only if it does not already exist, you can use the following syntax −CREATE OR REPLACE VIEW yourViewName AS SELECT *FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table createViewDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into createViewDemo(Name) values('John'); Query OK, 1 row affected (0.22 sec) mysql> insert into ...
Read MoreHow to check if a table exists in MySQL and create if it does not already exist?
If you try to create a table and the table name already exist then MySQL will give a warning message. Let us verify the concept.Here, we are creating a table that already exist −mysql> CREATE TABLE IF NOT EXISTS DemoTable ( CustomerId int, CustomerName varchar(30), CustomerAge int ); Query OK, 0 rows affected, 1 warning (0.05 sec)The table name DemoTable is already present. Let us check the warning message.Following is the query −mysql> show warnings;This will produce the following output i.e. the warning message −+-------+------+------------------------------------+ | Level | Code | Message ...
Read MoreCommand to check read/write ratio in MySQL?
To check the read/write ratio, you need to use SHOW STATUS command. This will give all the ratios.Case 1 − The syntax is as follows to get the read/write ratio −SHOW STATUS LIKE ‘Com_%’;Case 2 − If you want the insert, update, select and delete ratio, use the below syntax −SHOW GLOBAL STATUS WHERE Variable_name = 'Com_insert' OR Variable_name = 'Com_select' OR Variable_name = 'Com_Update' OR Variable_name = 'Com_delete';Here is no need to do any changes in the above syntax. The query is as follows −mysql> SHOW GLOBAL STATUS WHERE Variable_name = 'Com_insert' OR Variable_name = 'Com_select' OR -> ...
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