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MySQL Articles
Page 35 of 355
Group result in MySQL and show on list?
For this, use GROUP BY along with ORDER BY −select yourColumnName, count(*) as anyAliasName from yourTableName group by yourColumnName order by yourColumnName;Let us create a table −mysql> create table demo7 −> ( −> id int NOT NULL AUTO_INCREMENT, −> first_name varchar(50) −> , −> primary key(id) −> ); Query OK, 0 rows affected (1.22 sec)Insert some records into the table with the help of insert command −mysql> insert into demo7(first_name) values('John'); Query OK, 1 row affected (0.09 sec) mysql> insert into demo7(first_name) values('David'); Query OK, 1 row affected (0.22 sec) mysql> insert into demo7(first_name) values('John'); Query OK, 1 row affected ...
Read MoreMySQL Error ERROR 1099 (HY000): Table was locked with a READ lock and can't be updated
To get rid of LOCK TABLES query, you need to use UNLOCK TABLES.Let us create a table −mysql> create table demo6 −> ( −> country_name varchar(100 −> ) −> ); Query OK, 0 rows affected (1.51 sec)Insert some records into the table with the help of insert command −mysql> insert into demo6 values('US'); Query OK, 1 row affected (0.11 sec) mysql> insert into demo6 values('UK'); Query OK, 1 row affected (0.08 sec) mysql> insert into demo6 values('AUS'); Query OK, 1 row affected (0.11 sec)Display records from the table using select statement −mysql> select *from demo6;This will produce the ...
Read MoreLimit total number of results across tables in MySQL?
For this, you can use UNION ALL along with LIMIT concept. For our example, we will create three tables.Let us create the first table −mysql> create table demo3 −> ( −> value int −> ); Query OK, 0 rows affected (1.39 sec)Insert some records into the table with the help of insert command −mysql> insert into demo3 values(10); Query OK, 1 row affected (0.13 sec) mysql> insert into demo3 values(20); Query OK, 1 row affected (0.08 sec) mysql> insert into demo3 values(30); Query OK, 1 row affected (0.08 sec)Display records from the table using select statement −mysql> select ...
Read MoreMultiple LIKE Operators with ORDER BY in MySQL?
Following is the syntax implementing multiple LIKE operators with ORDER BY −select *from yourTableName order by ( yourColumnName like '%yourValue1%' ) + ( yourColumnName like '%yourValue2%' ) + . . N desc;Let us create a table −mysql> create table demo2 −> ( −> id int not null auto_increment, −> name varchar(100), −> primary key(id) −> ); Query OK, 0 rows affected (1.53 sec)Insert some records into the table with the help of insert command −mysql> insert into demo2(name) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into demo2(name) values('David'); Query OK, 1 row affected (0.09 ...
Read MoreHow to get number located at 2 places before decimal point MySQL?
In order to get number located at 2 places before decimal point, you can use the concept of div.Let us create a table −mysql> create table demo1 −> ( −> value float −> ); Query OK, 0 rows affected (2.20 sec)Insert some records into the table with the help of insert command −mysql> insert into demo1 values(456.54); Query OK, 1 row affected (0.16 sec) mysql> insert into demo1 values(50.64); Query OK, 1 row affected (0.17 sec) mysql> insert into demo1 values(1000.78); Query OK, 1 row affected (0.13 sec)Display records from the table using select statement −mysql> select *from demo1;This will ...
Read MoreHow to select subsets of data In SQL Query Style in Pandas?
IntroductionIn this post, I will show you how to perform Data Analysis with SQL style filtering with Pandas. Most of the corporate company’s data are stored in databases that require SQL to retrieve and manipulate it. For instance, there are companies like Oracle, IBM, Microsoft having their own databases with their own SQL implementations.Data scientists have to deal with SQL at some stage of their career as the data is not always stored in CSV files. I personally prefer to use Oracle, as the majority of my company’s data is stored in Oracle.Scenario – 1 Suppose we are given a ...
Read MoreSum of the first and last digit of a number in PL/SQL
In this problem, we are given a number n. Our task is to create a program to find the sum of the first and last digit of a number in PL/SQL.First, let’s brush-up about PL/SQL, PL/SQL is a combination of SQL along with the procedural features of programming languages.Let’s take an example to understand the problem, Input − n = 31415Output − 8Explanation − first digit = 3 , last digit = 5. Sum = 8To, solve this problem, we will extract the first and last digit to number n. And the print their sum.The first and last digits are ...
Read MoreCan I query how much disk space certain rows or columns are taking up in MySQL?
Yes, using the below syntax −select * from information_schema.tables where table_name=yourTableName;Let us first create a table −mysql> create table DemoTable1600 -> ( -> StudentId int, -> StudentFirstName varchar(20) -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1600 values(100, 'Bob'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1600 values(101, 'David'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1600 values(102, 'Carol'); Query OK, 1 row affected (0.19 sec)Display all records from the table using select statement −mysql> select * from ...
Read MoreHow to combine duplicate values into one with corresponding value separated by hyphens in MySQL?
To combine, use GROUP_CONCAT() function to combine some attributes in two rows into one. As a separator, use hyphens.Let us first create a table −mysql> create table DemoTable1386 -> ( -> Title varchar(255), -> Name varchar(60) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1386 values('Introduction to MySQL', 'Paul DuBois'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1386 values('Java in Depth', 'Khalid Mughal'); Query OK, 1 row affected (0.48 sec) mysql> insert into DemoTable1386 values('Introduction to MySQL', 'Russell Dyer'); Query OK, ...
Read MoreImplement numbering in MySQL GROUP_CONCAT
Let us first create a table −mysql> create table DemoTable1627 -> ( -> FirstName varchar(20), -> LastName varchar(20) -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command.mysql> insert into DemoTable1627 values('John', 'Smith'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1627 values('John', 'Doe'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1627 values('Adam', 'Smith'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1627 values('Carol', 'Taylor'); Query OK, 1 row affected (0.08 sec)Display all records from the table using ...
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