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Database Articles
Page 484 of 546
How to query a key having space in its name with MongoDB?
To query a key having space in its name, you can use dot(.) notation.Step 1: First, you need to create a set in which a key has space in its name. Following is the query:> myValues["Details"] = {} { } > myValues["Details"]["Student Name"]="John"; John > myValues["Details"]["StudentAge"]=26; 26Step 2: Now you need to create a collection and store the above set as a document. Following is the query> db.keyHavingSpaceDemo.insertOne( myValues); { "acknowledged" : true, "insertedId" : ObjectId("5ca27e3b6304881c5ce84ba4") }Following is the query to display all documents from a collection with the help of find() method> db.keyHavingSpaceDemo.find().pretty();This will produce the following ...
Read MoreHow to project specific fields from a document inside an array in Mongodb?
To project specific fields from a document inside an array, you can use positional ($) operator.Let us first create a collection with documents> db.projectSpecificFieldDemo.insertOne( ... { ... "UniqueId": 101, ... "StudentDetails" : [{"StudentName" : "Chris", "StudentCountryName ": "US"}, ... {"StudentName" : "Robert", "StudentCountryName" : "UK"}, ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5ca27aeb6304881c5ce84ba2") } > db.projectSpecificFieldDemo.insertOne( { "UniqueId": 102, "StudentDetails" : [{"StudentName" : "Robert", "StudentCountryName ": "UK"}, {"StudentName" : "David", "StudentCountryName" : "AUS"}, ] ...
Read MoreHow to drop a numeric collection from MongoDB?
In order to remove the numeric collection name, use the following syntaxdb.getCollection("yourNumericCollectionName").drop();First, create a numeric collection. Following is the query> db.createCollection("2536464"); { "ok" : 1 }Now insert some documents in the above collection. Following is the query> db.getCollection("2536464").insertOne({"Record":1}); { "acknowledged" : true, "insertedId" : ObjectId("5ca254a46304881c5ce84b8e") } > db.getCollection("2536464").insertOne({"Record":2}); { "acknowledged" : true, "insertedId" : ObjectId("5ca254a76304881c5ce84b8f") } > db.getCollection("2536464").insertOne({"Record":3}); { "acknowledged" : true, "insertedId" : ObjectId("5ca254a96304881c5ce84b90") }Following is the query to display all documents from a collection with the help of find() method> db.getCollection("2536464").find().pretty();This will produce the following output{ "_id" : ObjectId("5ca254a46304881c5ce84b8e"), "Record" : 1 ...
Read MoreMongoDB equivalent of WHERE IN(1,2,…)?
The MongoDB equivalent of WHERE IN(1, 2, ....) is $in operator. The syntax is as followsdb.yourCollectionName.find({yourFieldName:{$in:[yourValue1, yourValue2, ....N]}}).pretty();Let us first create a collection with documents> db.whereInDemo.insertOne({"StudentName":"John", "StudentMathScore":57}); { "acknowledged" : true, "insertedId" : ObjectId("5ca281ec6304881c5ce84ba5") } > db.whereInDemo.insertOne({"StudentName":"Larry", "StudentMathScore":89}); { "acknowledged" : true, "insertedId" : ObjectId("5ca281f56304881c5ce84ba6") } > db.whereInDemo.insertOne({"StudentName":"Chris", "StudentMathScore":98}); { "acknowledged" : true, "insertedId" : ObjectId("5ca281fd6304881c5ce84ba7") } > db.whereInDemo.insertOne({"StudentName":"Robert", "StudentMathScore":99}); { "acknowledged" : true, "insertedId" : ObjectId("5ca2820a6304881c5ce84ba8") } > db.whereInDemo.insertOne({"StudentName":"Bob", "StudentMathScore":97}); { "acknowledged" : true, "insertedId" : ObjectId("5ca282206304881c5ce84ba9") }Following is the query to display all documents from a collection with ...
Read MoreHow to return static strings in MySQL?
In order to return static strings in MySQL, you can use UNION. Following is the syntax −select 'yourStringValue1' as yourAliasName UNION select 'yourStringValue2' as yourAliasName;Let us implement the above syntax to return static strings in MySQL. Following is the query −mysql> select 'HELLO' as staticStringsResult -> UNION -> select 'MySQL' as staticStringsResult;This will produce the following output −+---------------------+ | staticStringsResult | +---------------------+ | HELLO | | MySQL | +---------------------+ 2 rows in set (0.00 sec)In some MySQL versions, the above syntax does not work, therefore you ...
Read MoreMongoDB order by two fields sum?
To order by two fields sum, you can use the aggregate framework. Let us first create a collection with documents> db.orderByTwoFieldsDemo.insertOne({"Value1":10, "Value2":35}); { "acknowledged" : true, "insertedId" : ObjectId("5ca285576304881c5ce84baa") } > db.orderByTwoFieldsDemo.insertOne({"Value1":12, "Value2":5}); { "acknowledged" : true, "insertedId" : ObjectId("5ca2855f6304881c5ce84bab") } > db.orderByTwoFieldsDemo.insertOne({"Value1":55, "Value2":65}); { "acknowledged" : true, "insertedId" : ObjectId("5ca285686304881c5ce84bac") }Following is the query to display all documents from a collection with the help of find() method> db.orderByTwoFieldsDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5ca285576304881c5ce84baa"), "Value1" : 10, "Value2" : 35 } { "_id" : ObjectId("5ca2855f6304881c5ce84bab"), "Value1" ...
Read MoreHow to search for “ñ” and avoid records that include “n” in MySQL?
If you do not want all records that include “n” when you search for “ñ”, use the following syntax −select *from yourTableName where yourColumnName LIKE '%ñ%' COLLATE utf8_spanish_ci;Let us first create a table. Following is the query −mysql> create table NotIncludenDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ClientName varchar(20) -> ); Query OK, 0 rows affected (1.07 sec)Following is the query to insert some records in the table using insert command −mysql> insert into NotIncludenDemo(ClientName) values('John'); Query OK, 1 row affected (0.21 sec) mysql> insert into NotIncludenDemo(ClientName) values('Johñ'); Query OK, ...
Read MoreFinding highest value from sub-arrays in MongoDB documents?
To find the highest value from sub-arrays in documents, you can use an aggregate framework. Let us first create a collection with documents> db.findHighestValueDemo.insertOne( ... { ... _id: 10001, ... "StudentDetails": [ ... { "StudentName": "Chris", "StudentMathScore": 56}, ... { "StudentName": "Robert", "StudentMathScore":47 }, ... { "StudentName": "John", "StudentMathScore": 98 }] ... } ... ); { "acknowledged" : true, "insertedId" : 10001 } > db.findHighestValueDemo.insertOne( ... { ... _id: 10002, ... "StudentDetails": [ ...
Read MoreSet Blank spaces in column names with MySQL?
To set blank spaces in column names with MySQL, you can use the concept of backticks. Let us first create a table. Following is the query −mysql> create table blankSpacesDemo -> ( -> `Student Id` int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> `Student Full Name` varchar(100) -> ); Query OK, 0 rows affected (0.51 sec)Following is the query to insert some records in the table using insert command −mysql> insert into blankSpacesDemo(`Student Full Name`) values('John Smith'); Query OK, 1 row affected (0.16 sec) mysql> insert into blankSpacesDemo(`Student Full Name`) values('Carol Taylor'); Query OK, 1 row ...
Read MoreGet number of updated documents in MongoDB?
To get number of updated documents in MongoDB, you need to use runCommand along with getlasterror.Let us first create a collection with documents> db.getNumberOfUpdatedDocumentsDemo.insertOne({"StudentName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca28c1d6304881c5ce84bad") } > db.getNumberOfUpdatedDocumentsDemo.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca28c226304881c5ce84bae") } > db.getNumberOfUpdatedDocumentsDemo.insertOne({"StudentName":"Robert"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca28c276304881c5ce84baf") } > db.getNumberOfUpdatedDocumentsDemo.insertOne({"StudentName":"Ramit"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca28c366304881c5ce84bb0") } > db.getNumberOfUpdatedDocumentsDemo.insertOne({"StudentName":"Adam"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca28c436304881c5ce84bb1") }Following is the query to display all documents from a collection with the help of find() method:> db.getNumberOfUpdatedDocumentsDemo.find().pretty();This will ...
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