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Articles by George John
Page 65 of 79
How to get the longest VarChar length in MySQL?
To get the longest varchar length, you need to use CHAR_LENGTH().The syntax is as followsSELECT Max(CHAR_LENGTH(yourColumnName)) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table CharLengthDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Sentence varchar(255) - > ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into CharLengthDemo(Sentence) values('Java is an object oriented programming language' - > ); Query OK, 1 row ...
Read MoreConvert IntStream to String in Java
If you have IntStream with ASCII values, then easily convert it to string using the below given example.For IntStream class, import the following packageimport java.util.stream.IntStream;Let’s say the following is our IntStreamIntStream stream = "Example".chars();Now, convert the IntStream to stringString str = stream.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString();The following is an example to convert IntStream to String in JavaExampleimport java.util.stream.IntStream; class Demo { public static void main(String[] args) { IntStream stream = "Example".chars(); System.out.println("The ASCII values..."); String str = stream.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString(); System.out.println("The ...
Read MoreGet MySQL DISTINCT to work correctly if the records contain whitespace?
To get distinct including whitespace, you can use below syntax −SELECT DISTINCT replace(yourColumnName, ' ', '') FROM yourTableName;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 (0.63 sec)Insert some records in the table using insert command −mysql>insert into DemoTable(Name) values('John '); Query OK, 1 row affected (0.14 sec) mysql>insert into DemoTable(Name) values(' John '); Query OK, 1 row affected (0.14 sec) mysql>insert into DemoTable(Name) values('John'); Query OK, 1 row affected (0.09 sec) mysql>insert into DemoTable(Name) values('Sam'); Query OK, 1 row affected (0.15 sec) ...
Read MoreEvaluation of Boolean expression
We write a program in 8085 in the assembly language just for the evaluation of only wo Boolean expressions of 4 variables by using the interface of logic controller. The output of the program should be logically tested automatically by the output by the input changing from the inputs from 0000, 0001, … to 1111 just to press any key.Let us say we want to evaluate the following Boolean expressions.First of all, truth table for the Boolean expressions is written down as shown in the following table.PQRSXY000010000100001010001100010010010100011010011100100001100101101010101100110000110111111000111100The inputs of the PQRS gets connected to PB3, PB2, PB1, and PB0 of ...
Read MoreResolve Unknown database in JDBC error with Java-MySQL?
This type of error occurs if you select any database that does not exist in MySQL. Let us first display the error of unknown database in JDBC.The Java code is as follows. Here, we have set the database as ‘onlinebookstore’, which does not exist:import java.sql.Connection; import java.sql.DriverManager; public class UnknownDatabaseDemo { public static void main(String[] args) { String JdbcURL = "jdbc:mysql://localhost:3306/onlinebookstore?useSSL=false"; String Username = "root"; String password = "123456"; Connection con = null; try { con = DriverManager.getConnection(JdbcURL, Username, password); ...
Read MoreDifference between count(*) and count(columnName) in MySQL?
The count(*) returns all rows whether column contains null value or not while count(columnName) returns the number of rows except null rows.Let us first create a table.Following is the querymysql> create table ifNotNullDemo -> ( -> Name varchar(20) -> ); Query OK, 0 rows affected (0.54 sec)Following is the query to insert some records in the table using insert command:mysql> insert into ifNotNullDemo values('Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into ifNotNullDemo values(''); Query OK, 1 row affected (0.13 sec) mysql> insert into ifNotNullDemo values('Robert'); Query OK, 1 row affected (0.24 sec) ...
Read MoreCan we order a MySQL result with mathematical operations?
Yes, we can order with mathematical operations using ORDER BY clause. Let us first create a table:mysql> create table orderByMathCalculation -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Quantity int, -> Price int -> ); Query OK, 0 rows affected (0.57 sec)Following is the query to insert some records in the table using insert command:mysql> insert into orderByMathCalculation(Quantity, Price) values(10, 50); Query OK, 1 row affected (0.21 sec) mysql> insert into orderByMathCalculation(Quantity, Price) values(20, 40); Query OK, 1 row affected (0.14 sec) mysql> insert into orderByMathCalculation(Quantity, Price) values(2, 20); Query ...
Read MoreHow to add column using alter in MySQL?
Following is the syntax to add column using alter in MySQL:alter table yourTableName add column yourColumnName yourDataType default yourValue;Let us first create a table:mysql> create table alterTableDemo -> ( -> Id int, -> Name varchar(10) -> ); Query OK, 0 rows affected (0.69 sec)Let us check the description of the table using DESC command. This displays Field, Type, Key, etc. of the table:mysql> desc alterTableDemo;This will produce the following output+-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | Id | int(11) | YES ...
Read MoreHow to suppress MySQL stored procedure output?
To suppress MySQL stored procedure output, you can use variable. Let us first create a table.mysql> create table person_information -> ( -> Id int, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.50 sec)Following is the query to insert some records in the table using insert command:mysql> insert into person_information values(100, 'John'); Query OK, 1 row affected (0.17 sec) mysql> insert into person_information values(101, 'Chris'); Query OK, 1 row affected (0.22 sec) mysql> insert into person_information values(102, 'Robert'); Query OK, 1 row affected (0.16 sec)Following is the query to display records from ...
Read MoreWrite a MySQL query equivalent to "SHOW TABLES" in sorted order?
Use INFORMATION_SCHEMA.TABLES to display tables in sorted order. The below syntax will give sorted list of tables in ascending order:select TABLE_NAME from INFORMATION_SCHEMA.TABLES where TABLE_SCHEMA= 'yourDatabaseName' order by TABLE_NAME;Following is the query to implement the equivalent to SHOW TABLES:mysql> select TABLE_NAME from INFORMATION_SCHEMA.TABLES -> where TABLE_SCHEMA= 'sample' order by TABLE_NAME;This will produce the following output+------------------------------------+ | TABLE_NAME | +------------------------------------+ | a | | accumulateddemo ...
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