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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL query to sum the Product Price values from similar columns for same customers and display the result in the same column
For this, use SUM() along with GROUP BY. Let us first create a table −mysql> create table DemoTable ( CustomerName varchar(100), Product_1_Price int, Product_2_Price int ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', 67, 89); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('David', 769, 890); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('David', 987, 1000); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('John', 900, 111); Query OK, 1 row affected (0.12 sec)Display ...
Read MoreDisplay records by first fixing the first two values in a column and then using DISTINCT to display other values in MySQL
Let us first create a table −mysql> create table DemoTable ( FirstName varchar(100) ); Query OK, 0 rows affected (0.96 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Robert'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Mike'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-----------+ | FirstName | ...
Read MoreHow can I count unique records from a column in MySQL database?
For this, use aggregate function count(*) to count to GROUP BY to group. Let us first create a table −mysql> create table DemoTable ( UserName varchar(100), UserPostMessage text ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 'Hi'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values('David', 'Hello'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('Chris', 'Awesome'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('Chris', 'Amazing'); Query OK, 1 row affected (0.17 sec) mysql> insert ...
Read MoreMySQL query to display records ordered by DESC while skipping some?
Let us first create a table −mysql> create table DemoTable ( Id int, Name varchar(100) ); Query OK, 0 rows affected (0.94 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 'Chris'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(1, 'David'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(4, 'Bob'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(6, 'Sam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(7, 'Mike'); Query OK, 1 row affected (0.10 sec) mysql> insert ...
Read MoreFind the next lowest number higher than a certain number in MySQL?
For this, use aggregate function MIN() along with WHERE clause. Let us first create a table −mysql> create table DemoTable ( Number int ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(11); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(9); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(12); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This ...
Read MoreMySQL query to change a string by displaying only the part of string after underscore?
Let us first create a table −mysql> create table DemoTable ( UserName varchar(100) ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Smith_John'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Smith_Adam'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Smith_David'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Smith_Mike'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-------------+ | UserName ...
Read MoreMySQL query to find expiry date (record) from the next 2 days?
For this, you can use BETWEEN keyword. Let us first create a table −mysql> create table DemoTable ( ExpiryDate date ); Query OK, 0 rows affected (0.55 sec)Note − Let’s say the current date is 2019-08-18.Insert some records in the table using insert command −mysql> insert into DemoTable values('2018-01-21'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('2019-08-20'); Query OK, 1 row affected (0.39 sec) mysql> insert into DemoTable values('2018-08-20'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values('2019-08-21'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select ...
Read MoreMySQL query to find the average of rows with the same ID
Let us first create a table −mysql> create table DemoTable ( StudentId int, StudentMarks int ); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1000, 78); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(1001, 88); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values(1000, 89); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(1000, 67); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(1000, 90); Query OK, 1 row affected (0.21 sec) mysql> insert ...
Read MoreHow can I create a MySQL boolean column and assign value 1 while altering the same column?
To assign value 1 while altering, use the MySQL DEFAULT. This will itself enter 1 if nothing is inserted in the same column while using the INSERT command.Let us first create a table −mysql> create table DemoTable ( isAdult int ); Query OK, 0 rows affected (1.39 sec)Following is how you can assign value 1 default to the already created column −mysql> alter table DemoTable CHANGE isAdult isAdult BOOLEAN DEFAULT '1' NOT NULL; Query OK, 0 rows affected (1.18 sec) Records: 0 Duplicates: 0 Warnings: 0Insert some records in the table using insert command −mysql> insert into DemoTable values(); ...
Read MoreMySQL query to find the number of rows in the last query
For this, use the FOUND_ROWS in MySQL. Following is the syntax −SELECT SQL_CALC_FOUND_ROWS TABLE_NAME FROM `information_schema`.tables WHERE TABLE_NAME LIKE "yourValue%" LIMIT yourLimitValue;Here, I am using the database ‘web’ and I have lots of tables, let’s say which begins from DemoTable29. Let us implement the above syntax to fetch only 4 of such rows −mysql> SELECT SQL_CALC_FOUND_ROWS TABLE_NAME FROM `information_schema`.tables WHERE TABLE_NAME LIKE "DemoTable29%" LIMIT 4;This will produce the following output −+--------------+ | TABLE_NAME | +--------------+ | demotable29 | | demotable290 | | demotable291 | | demotable292 | +--------------+ 4 rows in set (0.01 sec)Here is the query ...
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