Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Database Articles
Page 231 of 547
How do I select 5 random rows from the 20 most recent rows in MySQL?
For random, use RAND() method. And for limit on rows, use the LIMIT() method.Let us first create a table −mysql> create table DemoTable -> ( -> ShippingDate datetime -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-01'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('2019-01-03'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2019-01-05'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('2019-01-07'); Query OK, 1 row affected (0.11 sec) ...
Read MoreMySQL query to find a value appearing more than once?
Let us first create a table −mysql> create table DemoTable -> ( -> value int -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.24 sec) ...
Read MoreCompare two tables and return missing ids using MySQL LEFT OUTER JOIN
To compare two tables and return missing ids, you need to use MySQL LEFT OUTER JOIN.Let us create a table with sample fields and then we will insert records. The query to create the first table −First_Tablemysql> create table First_Table -> ( -> Id int -> ); Query OK, 0 rows affected (0.88 sec)Now insert some records in the table using insert command. The query is as follows −mysql> insert into First_Table values(1); Query OK, 1 row affected (0.68 sec) mysql> insert into First_Table values(2); Query OK, 1 row affected (0.29 sec) mysql> insert into First_Table values(3); ...
Read MoreSelect all rows except from today in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(100), -> DueDate datetime -> ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command. Let’s say the current date is “2019-07-03” −mysql> insert into DemoTable values('Chris', '2019-06-24'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Chris', '2018-01-01'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Robert', '2019-07-03'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Carol', '2019-08-03'); Query OK, 1 row affected (0.22 ...
Read MoreHow to select return value from MySQL prepared statement?
Let us create a stored procedure and select return value from MySQL prepared statement −mysql> DELIMITER // mysql> CREATE PROCEDURE return_value() -> BEGIN -> SET @returnQuery= 'SELECT 98 INTO @value'; -> PREPARE stmt FROM @returnQuery; -> EXECUTE stmt; -> END -> // Query OK, 0 rows affected (0.20 sec) mysql> DELIMITER ;Call stored procedure using CALL command.mysql> call return_value(); Query OK, 1 row affected (0.07 sec)Display value using select statement −mysql> select @value;outputThis will produce the following output −+--------+ | @value | +--------+ | 98 | +--------+ 1 row in set (0.00 sec)
Read MoreCan I get the count of repeated values in a column with MySQL?
Yes, you can use ORDER BY DESC with GROUP BY. Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> PostMessage varchar(100) -> ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(PostMessage) values('Hi'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(PostMessage) values('Hello'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(PostMessage) values('Hi'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(PostMessage) values('Awesome'); Query OK, ...
Read MoreHow to count number of NULLs in a row with MySQL?
Use ISNULL() from MySQL. Let us first create a table −mysql> create table DemoTable -> ( -> Number1 int, -> Number2 int -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, NULL); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(NULL, NULL); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(29, 98); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(NULL, 119); Query OK, 1 row affected (0.15 sec)Display all records ...
Read MoreMySQL: What is 'AUTO_INCREMENT=5' in a create table query?
The AUTO_INCREMENT=5 in a create table query tells that the first record will start from 5 i.e. not default 1. As we know if you do not set the value to AUTO_INCREMENT then MySQL starts from 1 by default.The syntax is as follows:CREATE TABLE yourTableName ( yourColumnName1 dataType NOT NULL AUTO_INCRMENT, . . . N, PRIMARY KEY(yourColumnName1 ) )AUTO_INCREMENT=5;To understand the above syntax, let us create a table.Case1 − The table starts auto increment from 1 because it is the default standard.The query to create a table is as follows:mysql> create table defaultAutoIncrementDemo -> ( -> Id int ...
Read MoreHow to use if clause in MySQL to display Students result as Pass or Fail in a new column?
Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(100), -> Subject varchar(100), -> Score int -> ); Query OK, 0 rows affected (0.94 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name, Subject, Score) values('Chris', 'MySQL', 80); Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable(Name, Subject, Score) values('Robert', 'MongoDB', 45); Query OK, 1 row affected (0.62 sec) mysql> insert into DemoTable(Name, Subject, Score) values('Adam', 'Java', 78); Query OK, 1 row affected ...
Read MoreDisplay records ignoring NULL in MySQL
Use IS NOT NULL to display only NOT NULL records. Let us first create a table −mysql> create table DemoTable -> ( -> FirstName varchar(100) -> ); Query OK, 0 rows affected (3.01 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.44 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.58 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.20 sec) mysql> insert into ...
Read More