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MySQL Articles
Page 232 of 355
Select records from a table on the basis of keywords in MySQL
Let’s say some of the columns values in a table has a specific keyword and you want only those records. For this, use the LIKE operator.Let us first see an example and create a table −mysql> create table DemoTable750 (Title varchar(200)); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable750 values('Java and MongoDB, MySQL'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable750 values('MySQL, SQL Server'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable750 values('PL/SQL, Python, MongoDB'); Query OK, 1 row affected (0.14 sec) mysql> ...
Read MoreList logged-in MySQL users?
To list logged-in MySQL users, you can use any of the following two methods −First MethodUse INFORMATION_SCHEMA.PROCESSLISTselect *from INFORMATION_SCHEMA.PROCESSLIST;Second MethodYou can use SHOW PROCESSLIST command as well. Following is the syntax −SHOW PROCESSLIST;Let us implement the above syntaxes in order to list logged in MySQL users −mysql> select *from information_schema.processlist;This will produce the following output -+----+-----------------+-----------------+------+---------+--------+-----------------------------+---------------------------------------------+ | ID | USER | HOST | DB | COMMAND | TIME | STATE | INFO ...
Read MoreUpdate all the zero values with a custom value in MySQL with a function similar to ISNULL()
For this, you can use custom IF() and set a value whenever 0 appears.Let us first create a table −mysql> create table DemoTable749 (Value int); Query OK, 0 rows affected (1.02 sec)Insert some records in the table using insert command −mysql> insert into DemoTable749 values(10); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable749 values(0); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable749 values(769); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable749 values(0); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable749 values(78); Query OK, 1 row affected (0.14 sec) ...
Read MoreMySQL query to extract only the day instead of entire date
To extract only the day instead of the entire date, you need to use DAYOFMONTH() function from MySQL.Let us first create a table −mysql> create table DemoTable747 (DueDate datetime); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable747 values('2019-01-31') ; Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable747 values('2018-12-01'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable747 values('2017-09-14'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable747 values('2016-07-21'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select ...
Read MoreMySQL query to display only the empty and NULL values together?
To check for NULL, use the IS NULL. For empty values, you need to check with an empty string. We will now see an example.Let us first create a table −mysql> create table DemoTable691( PlayerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, PlayerName varchar(100), PlayerScore int ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable691(PlayerName, PlayerScore) values('Robert', 56); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable691(PlayerName, PlayerScore) values('David', 89); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable691(PlayerName, PlayerScore) values('', 98); Query ...
Read MoreWill "create table table" work in MySQL since we cannot use reserved words as table name?
Let us first see a case wherein we use “create table table” while creating a table. An error will arise −mysql> create table table( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(100) );This will produce the following output i.e. error −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'table( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(100) )' at line 1As you can see above, the word “table” is a reserved keyword, and we ...
Read MoreHow to select records that begin with a specific value in MySQL?
To select records that begin with a specific value, you need to use LIKE operator. Let us first create a table −mysql> create table DemoTable690( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserValue varchar(100) ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable690(UserValue) values('567890'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable690(UserValue) values('789032'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable690(UserValue) values('567342'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable690(UserValue) values('890678'); Query OK, 1 row affected (0.16 sec)Display ...
Read MoreHow to find missing value between two MySQL Tables?
To find missing value between two MySQL tables, use NOT IN. Let us first create a table −mysql> create table DemoTable1(Value int); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(1); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(2); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable1 values(5); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable1 values(6); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1 values(8); Query OK, 1 row affected (0.16 sec)Display all records from ...
Read MoreMySQL query to insert data from another table merged with constants?
Let us first create a table −mysql> create table DemoTable1(Name varchar(100)); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values('John'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1 values('Chris'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1 values('Robert'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following output −+--------+ | Name | +--------+ | John | | Chris | | Robert | +--------+ 3 ...
Read MoreWorking with MySQL WHERE.. OR query with multiple OR usage. Is there an alternative?
Yes, an alternative for MySQL “WHERE.. OR” is using REGEXP.Let us first create a table −mysql> create table DemoTable684(EmployeeInformation text); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable684 values('John 21 Google'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable684 values('Carol 23 Amazon'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable684 values('Carol 26 Flipkart'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable684 values('David 29 Microsoft'); Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −mysql> ...
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