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Let us first create a table −mysql> create table DemoTable1572 -> ( -> StudentId int, -> StudentMarks int, -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1572 values(1, 79, 'Sam'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1572 values(2, 89, 'Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1572 values(3, 98, 'David'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1572 values(4, 79, 'Bob'); Query OK, 1 row affected (0.10 sec)Display all ... Read More
To insert an IF statement into a MySQL query, use the below syntax::select yourColumnName ,if(yourCondition, yourStatement1, yourStatement2) from yourTableName;Let us first create a table −mysql> create table DemoTable1571 -> ( -> Id int, -> Value int -> ); Query OK, 0 rows affected (5.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1571 values(101, 500); Query OK, 1 row affected (1.07 sec) mysql> insert into DemoTable1571 values(102, 450); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable1571 values(103, 300); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1571 ... Read More
You need to use port number 3306 in the URL. The syntax is as follows −jdbc:mysql://localhost:3306Exampleimport java.sql.Connection; import java.sql.DriverManager; public class MySQLConnectionToJava { public static void main(String[] args) { String JDBCURL="jdbc:mysql://localhost:3306/sample?useSSL=false"; Connection con=null; try { con = DriverManager.getConnection(JDBCURL,"root","123456"); if(con!=null) { System.out.println("MySQL connection is successful with port 3306."); } } catch(Exception e) { e.printStackTrace(); } } }OutputMySQL connection is successful with port 3306.
Let us first create a table −mysql> create table DemoTable1570 -> ( -> ArrivalTime datetime -> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1570 values('2019-10-15 5:10:00'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable1570 values('2019-10-15 23:00:00'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1570 values('2019-10-15 23:10:00'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1570 values('2019-10-15 16:10:00'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select * from DemoTable1570;This ... Read More
Let us first create a table −mysql> create table DemoTable1569 -> ( -> StudentId varchar(10), -> StudentName varchar(20) -> ); Query OK, 0 rows affected (3.05 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1569 values('John_12', 'John Smith'); Query OK, 1 row affected (0.38 sec) mysql> insert into DemoTable1569 values('David_321', 'Carol Taylor'); Query OK, 1 row affected (0.50 sec) mysql> insert into DemoTable1569 values('David_989', 'David Miller'); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select * from DemoTable1569;This will produce the following output+-----------+--------------+ | ... Read More
To fetch total number of table rows across databases, use aggregate function SUM() along with INFORMATION SCHEMA. Let us first create a table, which is in “web” database −mysql> create table DemoTable1568 -> ( -> Name varchar(20) -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1568 values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1568 values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1568 values('David'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select ... Read More
To get the last 30 rows in MySQL, you need to use ORDER BY DESC and then LIMIT 30. The syntax is as follows −select * from yourTableName order by yourColumnName DESC LIMIT 30;Let us first create a table −mysql> create table DemoTable1567 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1567 values(), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ... Read More
You have to use the fdatasync(fd) function to force write of file with filedescriptor fd to disk. It does not force update of metadata. Also note that this is only available on Unix.A more cross platform solution would be to use fsync(fd) as it force write of file with filedescriptor fd to disk. On Unix, this calls the native fsync() function; on Windows, the MS _commit() function.Exampleimport os, sys # Open a file fd = os.open( "foo.txt", os.O_RDWR|os.O_CREAT ) os.write(fd, "This is test") # Now you can use fsync() method. os.fsync(fd) # Now read this file from the beginning os.lseek(fd, ... Read More
You can change the owner of a file or a directory using the pwd, grp and os modules. The uid module is used to get the uid from user name, grp to get gid group name string and os to change the owner:Exampleimport pwd import grp import os uid = pwd.getpwnam("my_name").pw_uid gid = grp.getgrnam("my_group").gr_gid path = 'my_folder' os.chown(path, uid, gid)
For this, you can use CASE WHEN statement. Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(20) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(''); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(''); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> ... Read More