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Database Articles
Page 448 of 547
How can I order in group but randomly with MySQL?
Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Value char(1) ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Value) values('X'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Value) values('Y'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable(Value) values('X'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable(Value) values('X'); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable(Value) values('Y'); Query OK, 1 ...
Read MoreHow to get MySQL combined field result?
You can use CONCAT() function from MySQL for this. Let us first create a table −mysql> create table DemoTable ( ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientFirstName varchar(20), ClientLastName varchar(20) ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(ClientFirstName, ClientLastName) values('John', 'Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(ClientFirstName, ClientLastName) values('John', 'Miller'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(ClientFirstName, ClientLastName) values('Carol', 'Taylor'); Query OK, 1 row affected (0.13 sec) mysql> insert into ...
Read MoreNew line separator doesn't work for group_concat function in MySQL? How to use it correctly?
To use new line separator in group_concat() function, follow the below syntax −select group_concat(concat_ws(' ', yourColumnName1, yourColumnName2) SEPARATOR "\r") from yourTableName;Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(20), LastName varchar(20) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstName, LastName) values('John', 'Smith'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(FirstName, LastName) values('David', 'Miller'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(FirstName, LastName) values('John', 'Doe'); ...
Read MorePreserve select order within MySQL UNION?
It’s a good choice to use CASE statement. Do not use UNION. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, ShippingDate datetime ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(ShippingDate) values('2019-04-21'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(ShippingDate) values('2019-01-01'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(ShippingDate) values('2019-05-11'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(ShippingDate) values('2018-12-31'); Query OK, 1 row ...
Read MoreImplement Conditional MySQL Query in a stored procedure?
For conditional MySQL query, you can use IF ELSE concept in stored procedure. Let us first create a table −mysql> create table DemoTable1 ( Id int ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1 values(20); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1 values(30); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following output ...
Read MoreHow to prevent a user from accessing a specific schema in MySQL?
To prevent a user from accessing a specific schema, you need to use delete command. Following is the syntax −DELETE FROM mysql.db WHERE Db IN("yourSpecificSchema", "yourSpecificSchema\_%") AND User = "yourUserName" AND Host = "yourHostName";Let us implement the above syntax to prevent a user from accessing a specific schema. First of all, let us display all users and host from MySQL.user table.mysql> select user, host from MySQL.user;This will produce the following output −+------------------+-----------+ | user | host | +------------------+-----------+ | Bob | % ...
Read MoreHow to search by specific pattern in MySQL?
You can use regular expression for this. Let us first create a table −mysql> create table DemoTable ( UserId varchar(100) ); Query OK, 0 rows affected (1.28 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('User-123-G'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Us-453-GO'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values('TRUE-908-K'); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------------+ | UserId | ...
Read MoreHow to make MySQL table primary key auto increment?
To make MySQL table primary key auto increment, use the below syntaxCREATE TABLE yourTableName ( yourColumnName INT(6) ZEROFILL NOT NULL AUTO_INCREMENT, PRIMARY KEY(yourColumnName) );Let us first create a table and set primary key auto increment −mysql> CREATE TABLE DemoTable ( UserId INT(6) ZEROFILL NOT NULL AUTO_INCREMENT, PRIMARY KEY(UserId) ); Query OK, 0 rows affected (0.81 sec)Insert some records in the table using insert command −mysql> INSERT INTO DemoTable values(); Query OK, 1 row affected (0.12 sec) mysql> INSERT INTO DemoTable values(); Query OK, 1 row affected (0.13 sec) mysql> INSERT ...
Read MoreMySQL Select displaying Data type in a separate column?
You can use INFORMATION_SCHEMA.COLUMNS for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(20) ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name) values('Chris'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(Name) values('Robert'); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable(Name) values('Sam'); 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 ...
Read MoreWhat is the Difference Between a Block chain and a Database?
The difference between a Block chain and a traditional database begins with architecture, creation, access, and permissions. They differ in each and every aspect except that they both are huge repositories of data which is stored and accessed in an organised form, digitally.DatabaseThis runs on a client-server network, where there is a central repository of data that will be accessed by those nodes who have permission to access the data. The data of the database is maintained by administrators, and mostly nodes will have access to retrieve the data as per their requirement.Database, which is an electronic collection of data ...
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