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Articles by karthikeya Boyini
Page 129 of 143
MySQL select order by acts like a string (not a number)?
You can use the following syntax if your column has varchar data type −select yourColumnName FROM yourTableName ORDER BY yourColumnName +0 DESC;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectOrderdemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(100), -> RankNumber varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into selectOrderdemo(Name, RankNumber) values('Larry', -100); Query OK, 1 row affected (0.23 ...
Read MoreMySQL Merge selects together?
To merge selects together, you need to use GROUP BY clause. To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table MergingSelectDemo -> ( -> RoomServicesId int, -> RoomId int, -> ServiceId int -> ); Query OK, 0 rows affected (1.98 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into MergingSelectDemo values(10, 10, 10); Query OK, 1 row affected (0.29 sec) mysql> insert into MergingSelectDemo values(20, 10, 20); Query OK, 1 row affected ...
Read MoreHow to copy data from one field to another on every row in MySQL?
To copy data from one field to another on every row, use the UPDATE command.Let us first create a table −mysql> create table DemoTable ( StudentId int, StudentFirstName varchar(20), StudentMarks int default 0 ); Query OK, 0 rows affected (0.49 sec)Following is the query to insert records in the table using insert command −mysql> insert into DemoTable(StudentId, StudentFirstName) values(89, 'Larry'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentId, StudentFirstName) values(35, 'Robert'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(StudentId, StudentFirstName) values(48, 'Chris'); Query OK, 1 row affected (0.13 sec) ...
Read MoreCreate array with MongoDB query?
You can use the concept of toArray() to create array. Following is the syntax −db.yourCollectonName.find({}, {yourFieldName:1}).toArray();Let us create a collection with documents −> db.createArrayDemo.insertOne({"UserName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbd6461de8cc557214c0e00") } > db.createArrayDemo.insertOne({"UserName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbd6467de8cc557214c0e01") } > db.createArrayDemo.insertOne({"UserName":"Robert"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbd646cde8cc557214c0e02") } > db.createArrayDemo.insertOne({"UserName":"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbd6470de8cc557214c0e03") }Display all documents from a collection with the help of find() method −> db.createArrayDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbd6461de8cc557214c0e00"), "UserName" : "Chris" } { "_id" : ObjectId("5cbd6467de8cc557214c0e01"), ...
Read MoreROW_NUMBER() equivalent in MySQL for inserting?
There is no equivalent of ROW_NUMBER() in MySQL for inserting but you can achieve this with the help of variable. The syntax is as follows −SELECT (@yourVariableName:=@yourVariableName + 1) AS `anyAliasName`, yourColumnName1, yourColumnName2, ...N FROM yourTableName ,(SELECT @yourVariableName:=0) AS anyAliasName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table RowNumberDemo -> ( -> UserId int, -> UserName varchar(20) -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The ...
Read MoreMySQL 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 ...
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