MongoDB query commands
1. query all records
Copy the Code as follows:
db.userInfo.find();
Equivalent:Select * from userInfo;
By default, 20 records are displayed on each page. If no record is displayed, you can use the it iteration command to query data on the next page. Note: Type
It commandCannot contain ";"
However, you can set the size of data displayed on each page.DBQuery. shellBatchSize = 50;In this way, 50 records are displayed on each page.
2. query duplicate data of a column in the current clustering set after Removal
Copy the Code as follows:
db.userInfo.distinct("name");
The same data in name is filtered out.
Equivalent:
Select distict name from userInfo;
3. query records with age = 22
Copy the Code as follows:
db.userInfo.find({"age": 22});
Equivalent:Select * from userInfo where age = 22;
4. query records of age> 22
Copy the Code as follows:
db.userInfo.find({age: {$gt: 22}});
Equivalent:Select * from userInfo where age> 22;
5. query records of age <22
Copy the Code as follows:
db.userInfo.find({age: {$lt: 22}});
Equivalent:Select * from userInfo where age <22;
6. query records with age> = 25
Copy the Code as follows:
db.userInfo.find({age: {$gte: 25}});
Equivalent:Select * from userInfo where age> = 25;
7. query records of age <= 25
Copy the Code as follows:
db.userInfo.find({age: {$lte: 25}});
8. query age> = 23 and age <= 26
Copy the Code as follows:
db.userInfo.find({age: {$gte: 23, $lte: 26}});
9. query data whose name contains mongo
Copy the Code as follows:
db.userInfo.find({name: /mongo/});
// Equivalent to %
Select * from userInfo where name like '% mongo % ';
10. query names starting with mongo
Copy the Code as follows:
db.userInfo.find({name: /^mongo/});
Select * from userInfo where name like 'mongo % ';
11. query the name and age data of a specified Column
Copy the Code as follows:
db.userInfo.find({}, {name: 1, age: 1});
Equivalent:
Select name, age from userInfo;
Of course, "true" or "false" can be used for name. If "true" is used, "river name: 1" has the same effect. If "false" is used, "name" is excluded and column information other than "name" is displayed.
12. query the name and age data of a specified column. age> 25
Copy the Code as follows:
db.userInfo.find({age: {$gt: 25}}, {name: 1, age: 1});
Equivalent:
Select name, age from userInfo where age> 25;
13. sort by age
Copy the Code as follows:
Ascending Order:
db.userInfo.find().sort({age: 1});
Descending order:
db.userInfo.find().sort({age: -1});
14. query data with name = zhangsan and age = 22
Copy the Code as follows:
db.userInfo.find({name: 'zhangsan', age: 22});
Equivalent:
Select * from userInfo where name = 'hangsan' and age = '22 ';
15. query the first five data entries
Copy the Code as follows:
db.userInfo.find().limit(5);
Equivalent:
Select top 5 * from userInfo;
16. Query 10 data records later
Copy the Code as follows:
db.userInfo.find().skip(10);
Equivalent:
Select * from userInfo where id not in (
Select top 10 * from userInfo
);
17. query data between 5-10
Copy the Code as follows:
db.userInfo.find().limit(10).skip(5);
Limit is the limit on the displayed quantity, and skip is the number of skipped.
18. or and query
Copy the Code as follows:
db.userInfo.find({$or: [{age: 22}, {age: 25}]});
Equivalent:
Select * from userInfo where age = 22 or age = 25;
19. query the first data entry.
Copy the Code as follows:
db.userInfo.findOne();
Equivalent:
Select top 1 * from userInfo;
Db. userInfo. find (). limit (1 );
20. query the number of records in a result set
Copy the Code as follows:
db.userInfo.find({age: {$gte: 25}}).count();
Equivalent:Select count (*) from userInfo where age> = 20;
21. sort by Column
Copy the Code as follows:
db.userInfo.find({sex: {$exists: true}}).count();
Equivalent:
Select count (sex) from userInfo;