To delete all rows older than 5 days, you can use the following syntax −delete from yourTableName    where datediff(now(), yourTableName.yourDateColumnName) > 5;Note − Let’s say the current date is 2019-03-10.To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table deleteRowsOlderThan5Demo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(100),    -> Post_Date date    -> ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into deleteRowsOlderThan5Demo(Name, Post_Date) ... Read More

To remove hyphens using MySQL update, you can use replace() function. The syntax is as follows −update yourTableName    set yourColumnName=replace(yourColumnName, '-', '' );To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table removeHyphensDemo    -> (    -> userId varchar(100)    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into removeHyphensDemo values('John-123-456'); Query OK, 1 row affected (0.22 sec) mysql> insert into removeHyphensDemo values('Carol-9999-7777-66555'); Query OK, 1 row affected (0.19 sec) ... Read More

To count the top 10 most occurring values in a column in MySQL, The syntax is as follows −SELECT yourColumnName, count(*)    FROM yourTableName    GROUP BY yourColumnName    ORDER BY count(*) DESC    LIMIT 10;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table countTop10Demo    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into countTop10Demo values(10); Query OK, 1 row affected (0.12 sec) ... Read More

To select dates in 30-day range, you can use arithmetic operation - with interval.The syntax is as follows −select *from yourTableName where yourDateColumnName > NOW() - INTERVAL 30 DAY and yourDateColumnName < NOW() + INTERVAL 30 DAY;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectDatesDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ArrivalDate datetime    -> ); Query OK, 0 rows affected (0.77 sec)Now you can insert some records in the table using insert command. The query is as ... Read More

Let us first create a demo table −mysql> create table selectPerson    -> (    -> PersonId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> PersonName varchar(20),    -> PersonFavouriteFruit varchar(60)    -> ); 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 selectPerson(PersonName, PersonFavouriteFruit) values('John', 'Banana'); Query OK, 1 row affected (0.14 sec) mysql> insert into selectPerson(PersonName, PersonFavouriteFruit) values('John', 'Blackberry'); Query OK, 1 row affected (0.12 sec) mysql> insert into selectPerson(PersonName, PersonFavouriteFruit) values('John', 'Blueberry'); Query OK, 1 row affected (0.12 sec) mysql> insert into selectPerson(PersonName, ... Read More

To test, use the sleep() function.Case 1 −The syntax is as follows −SELECT yourColumnName+sleep(yourIntegerValue) FROM yourTableName GROUP BY yourColumnName+sleep(yourIntegerValue);;Case 2 − You can use another syntax which is as follows −SELECT yourColumnName+sleep(yourIntegerValue) As anyAliasName FROM yourTableName GROUP BY yourAliasName;To understand the above syntaxes, let us create a table. The query to create a table is as follows −mysql> create table sleepDemo    -> (    -> value int    -> ); Query OK, 0 rows affected (1.25 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into sleepDemo values(40); Query OK, 1 row ... Read More

No, you cannot give the same name for view and table in MySQL.Let us first create a demo table −mysql> create table view_Table_Demo    -> (    -> Id int,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into view_Table_Demo values(100, 'Larry'); Query OK, 1 row affected (0.17 sec) mysql> insert into view_Table_Demo values(101, 'Mike'); Query OK, 1 row affected (0.20 sec) mysql> insert into view_Table_Demo values(102, 'Sam'); Query OK, 1 row affected (0.14 sec)Display all ... Read More

You can use SET command, but SET OPTIOn deprecated. Therefore, use SET SQL_SELECT_LIMIT.The syntax is as follows −SET SQL_SELECT_LIMIT=yourIntegerValue;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table MySQLSelectDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY    -> ); Query OK, 0 rows affected (0.99 sec)Insert some records in the table using insert command. The query is as follows −mysql> INSERT INTO MySQLSelectDemo VALUES(), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ... Read More

To get the highest value of a column in MongoDB, you can use sort() along with limit(1). The syntax is as follows −db.yourCollectionName.find().sort({"yourFieldName":-1}).limit(1);To understand the above syntax, let us create a collection with the document. The query to create a collection with a document is as follows −> db.gettingHighestValueDemo.insertOne({"Value":1029}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c900b885705caea966c5574") } > db.gettingHighestValueDemo.insertOne({"Value":3029}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c900b8d5705caea966c5575") } > db.gettingHighestValueDemo.insertOne({"Value":1092}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c900b925705caea966c5576") } > db.gettingHighestValueDemo.insertOne({"Value":18484}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c900b955705caea966c5577") } > db.gettingHighestValueDemo.insertOne({"Value":37474}); {    "acknowledged" ... Read More

You can use $where operator for this. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.queryInSameDocumentsDemo.insertOne({"StudentDetails":{"StudentName":"John"}, "NewStudentDetails":{"StudentName":"Carol"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c90096ed3c9d04998abf017") } > db.queryInSameDocumentsDemo.insertOne({"StudentDetails":{"StudentName":"Bob"}, "NewStudentDetails":{"StudentName":"Bob"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c900a435705caea966c5573") }Display all documents from a collection with the help of find() method. The query is as follows −> db.queryInSameDocumentsDemo.find().pretty();The following is the output −{    "_id" : ObjectId("5c90096ed3c9d04998abf017"),    "StudentDetails" : {       "StudentName" : "John"    },    "NewStudentDetails" : { ... Read More