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Database Articles
Page 386 of 547
Does UPDATE overwrite values if they are identical in MySQL
No, MySQL UPDATE won’t overwrite values if they are identical. Let us first create a table −mysql> create table DemoTable ( StudentId int, StudentMathMarks int, StudentMySQLMarks int ); Query OK, 0 rows affected (0.46 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1, 56, 78); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values(2, 88, 99); Query OK, 1 row affected (0.15 sec) mysql> inse rt into DemoTable values(3, 34, 98); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from ...
Read MoreCount from two tables and give combined count of string in MySQL?
To count, use the MySQL COUNT(*). However, with UNION ALL you would be able to get a combined count of string. Let us first create a table −mysql> create table DemoTable1 ( Name varchar(20) ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command. We are inserting string values in the first table −mysql> insert into DemoTable1 values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1 values('Robert'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1 values('Mike'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1 ...
Read MoreMySQL Stored Procedure calling with INT and VARCHAR values
To call a stored procedure, you can use CALL command. Following is the syntax −CALL yourStoredProcedureName(parameter if any);Let us first create a sample procedure. Following is the query to create a stored procedure. Here, we have set two values, one is an INT and another VARCHAR −mysql> DELIMITER // mysql> CREATE PROCEDURE CALL_PROC(Id int, Name varchar(40)) BEGIN SELECT CONCAT('You have entered the Id which is=', Id); SELECT CONCAT('You have entered the Name which is=', Name); END // Query OK, 0 rows affected (0.21 sec) mysql> DELIMITER ;Following is the query to call a stored procedure in ...
Read MoreHow to execute multiple select queries in MySQL ?
To execute multiple select queries in MySQL, use the concept of DELIMITER. Let us first create a table −mysql> create table DemoTable1 ( Title text )ENGINE=MyISAM; Query OK, 0 rows affected (0.30 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values('The database MySQL is less popular than MongoDB') ; Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable1 values('Java language uses MySQL database'); Query OK, 1 row affected (0.05 sec) mysql> insert into DemoTable1 values('Node.js uses the MongoDB') ; Query OK, 1 row affected (0.05 sec)Display all records from the table using ...
Read MoreWhy the following is showing an error in MySQL: INSERT INTO yourTableName VALUE(yourValue1,yourValue2,.......N);?
The error is in the syntax of VALUE().Use VALUES() instead of VALUE(). The correct syntax of the insert query is as follows −INSERT INTO yourTableName VALUES(yourValue1, yourValue2, .......N);Let us first create a table −mysql> create table DemoTable ( StudentId int, StudentName varchar(40), StudentAge int ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command −mysql> INSERT INTO DemoTable VALUES(1001, 'Tom', 20); Query OK, 1 row affected (0.11 sec) mysql> INSERT INTO DemoTable VALUES(1002, 'Mike', 21); Query OK, 1 row affected (0.13 sec) mysql> INSERT INTO DemoTable VALUES(1003, 'Sam', 19); Query OK, ...
Read MoreHow to create a new table from the first table using MySQL LIKE?
Let us first create a table −mysql> create table DemoTable1 ( EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, EmployeeName varchar(50) ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1(EmployeeName) values('Tom'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1(EmployeeName) values('Mike'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1(EmployeeName) values('Emma'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1(EmployeeName) values('Sam'); Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement::mysql> select *from DemoTable1;This will produce the ...
Read MoreHow to check the column values have string or digits in MySQL?
If you want only the string values, then use the below syntax −select *from yourTableName where yourColumnName NOT regexp '^[0-9]+$';If you want only the digit, then use the below syntax −select *from yourTableName where yourColumnName regexp '^[0-9]+$';Let us first create a table −mysql> create table DemoTable( Id varchar(100) ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('1000'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Carol_Smith'); Query OK, 1 row affected (0.15 ...
Read MoreInsert multiple values in a temporary table with a single MySQL query?
Let us first create a table −mysql> create temporary table DemoTable ( SerialNumber int ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command. Here, we are inserting multiple values in a temporary table −mysql> insert into DemoTable values(1),(2),(3),(4),(5),(6),(7),(8); Query OK, 8 rows affected (0.00 sec) Records: 8 Duplicates: 0 Warnings: 0Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------------+ | SerialNumber | +--------------+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | | 7 | | 8 | +--------------+ 8 rows in set (0.00 sec)
Read MoreCheck if the column values are the same among multiple records and set these records in a single row separated by a special character in MySQL
For this, you can use GROUP_CONCAT() along with DISTINCT. Let us first create a table −mysql> create table DemoTable ( Id int, Subject varchar(40) ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'MySQL'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(100, 'MongoDB'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(100, 'Java'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(100, 'MongoDB'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(101, 'MySQL'); ...
Read MoreMySQL query to display only the records that contains single word?
For this, you can filter records on the basis of LIKE. Let us first create a table −mysql> create table DemoTable ( Name varchar(50) ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John Smith'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Adam Smith'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Carol'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('David Miller'); Query OK, 1 ...
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