Trim X Number of Characters from the End in MySQL

AmitDiwan
Updated on 05-Nov-2019 06:45:55

322 Views

For this, you can use substring() along with length(). Let us first create a table −mysql> create table DemoTable1329    -> (    -> StudentName varchar(40)    -> ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1329 values('David Miller'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1329 values('Chris Brown'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1329 values('Adam Smith'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable1329 values('John Doe'); Query OK, 1 row affected (0.44 sec)Display all records from the ... Read More

Insert Values in a Table by MySQL SELECT from Another Table

AmitDiwan
Updated on 05-Nov-2019 06:41:53

962 Views

Fir this, use INSERT INTO SELECT statement. Let us first create a table −mysql> create table DemoTable1    -> (    -> Id int,    -> Name varchar(20),    -> Age int    -> ); Query OK, 0 rows affected (1.72 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(100, 'Chris', 24); Query OK, 1 row affected (0.61 sec) mysql> insert into DemoTable1 values(101, 'Adam', 23); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1 values(102, 'John', 25); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1 values(103, 'Carol', 26); Query ... Read More

Extract Time in Format Without Seconds from MySQL Query

AmitDiwan
Updated on 05-Nov-2019 06:38:25

387 Views

For this, you can use time_format(). Let us first create a table −mysql> create table DemoTable1326    -> (    -> Arrivaltime time    -> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1326 values('12:10:45'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1326 values('20:00:00'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1326 values('22:45:55'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1326 values('04:10:24'); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select * ... Read More

Order MySQL Results Without Identifier

AmitDiwan
Updated on 05-Nov-2019 06:35:51

156 Views

To order MySQL results without identifier, the syntax is as follows −select * from yourTableName order by 1 DESC LIMIT yourLimitValue;Let us first create a table −mysql> create table DemoTable1325    -> (    -> Id int,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1325 values(100, 'Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1325 values(101, 'Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1325 values(120, 'David'); Query OK, 1 row affected (0.14 sec) mysql> insert ... Read More

Identify Composite Primary Key in MySQL Database Table

AmitDiwan
Updated on 05-Nov-2019 06:28:38

2K+ Views

You can use aggregate function count(*). If it returns a value greater than 1, that would mean the table has composite primary key.Let us first create a table −mysql> create table DemoTable1324    -> (    -> StudentId int,    -> StudentName varchar(20),    -> StudentAge int,    -> StudentCountryName varchar(20)    -> ); Query OK, 0 rows affected (0.52 sec)Here is the query to add composite primary key −mysql> alter table DemoTable1324 ADD CONSTRAINT constr_IdAgeCountry PRIMARY KEY (StudentId, StudentAge, StudentCountryName); Query OK, 0 rows affected (1.29 sec) Records: 0 Duplicates: 0 Warnings: 0Following is the query to identify composite ... Read More

Get Last Created Table Name in MySQL

AmitDiwan
Updated on 05-Nov-2019 06:26:19

292 Views

You can use the concept INFORMATION_SCHEMA.TABLES for this. Let us first create a table. This would be our most recent table −mysql> create table DemoTable1323    -> (    -> FirstName varchar(10)    -> ); Query OK, 0 rows affected (0.43 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1323 values('Chris'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1323 values('David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1323 values('Bob'); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select *from DemoTable1323;This will produce ... Read More

Create MySQL Table from Existing Table Selecting Specific Rows

AmitDiwan
Updated on 04-Nov-2019 11:11:01

195 Views

To create a table from an already created table, use CREATE TABLE AS SELECT statement. Let us first create a table −mysql> create table DemoTable1318 -> ( -> Id int, -> FirstName varchar(10), -> LastName varchar(10), -> Age int -> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1318 values(1, 'Chris', 'Brown', 21); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable1318 values(2, 'David', 'Miller', 24); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1318 values(3, 'Carol', 'Taylor', 23); Query OK, 1 row affected (0.11 ... Read More

GetHashCode Method in C# CharEnumerator

AmitDiwan
Updated on 04-Nov-2019 11:08:18

97 Views

The CharEnumerator.GetHashCode() method in C# returns a hash code for the current object.Syntaxpublic virtual int GetHashCode ();Let us now see an example to implement the CharEnumerator.GetHashCode() method −Exampleusing System; public class Demo {    public static void Main(){       string strNum = "john";       CharEnumerator ch = strNum.GetEnumerator();       Console.WriteLine("HashCode = "+ch.GetHashCode());       while (ch.MoveNext())          Console.Write(ch.Current + " ");       // disposed       ch.Dispose();       // this will show an error since we disposed the object above       // Console.WriteLine(ch.Current);    } }OutputThis will produce the following output −HashCode = 30571253 j o h n

Dictionary Count Property in C#

AmitDiwan
Updated on 04-Nov-2019 11:05:31

512 Views

The Dictionary. Count property in C# gets the number of key/value pairs in the Dictionary.syntaxpublic int Count { get; }Let us now see an example to implement the Dictionary. Count property −Exampleusing System; using System.Collections.Generic; public class Demo {    public static void Main(){       Dictionary dict =       new Dictionary();       dict.Add("One", "Chris");       dict.Add("Two", "Steve");       dict.Add("Three", "Messi");       dict.Add("Four", "Ryan");       dict.Add("Five", "Nathan");       Console.WriteLine("Count of elements = "+dict.Count);       Console.WriteLine("Key/value pairs...");       foreach(KeyValuePair res in dict){ ... Read More

Return Multiple Results in MySQL Subquery with IN

AmitDiwan
Updated on 04-Nov-2019 10:59:21

378 Views

In MySQL, you can easily return multiple results, but also achieve this with subquery using IN(). Let us first create a table −mysql> create table DemoTable1317 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert commandmysql> insert into DemoTable1317(Name) values('Chris Brown'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1317(Name) values('John Doe'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1317(Name) values('Adam Smith'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1317(Name) values('John Smith'); ... Read More

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