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Articles by Kumar Varma
Page 4 of 9
Get part of a string based on a character in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> Code varchar(100) -> ); Query OK, 0 rows affected (1.07 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('/101/102/106'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('/110/111/101'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('/111/114/201'); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable values('/111/118'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce ...
Read MoreHow to add subtotal to a table column displaying NULL in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> Amount int, -> SubTotal int -> ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −ysql> insert into DemoTable(Amount) values(50); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Amount) values(60); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(Amount) values(70); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(Amount) values(80); Query OK, 1 row affected (0.17 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce ...
Read MoreCan we use "IF NOT IN" in a MySQL procedure?
Let us first see the syntax of IF NOT IN in MySQL −if(yourVariableName NOT IN (yourValue1, yourValue2, ........N) ) then statement1 else statement2 endif Let us implement the above syntax to use IF NOT IN −mysql> DELIMITER // mysql> CREATE PROCEDURE IF_NOT_INDemo(IN value int) -> BEGIN -> if(value NOT IN (10, 20, 30) ) then -> select "Value Not Found"; -> else -> select "Value Found"; -> end if; -> END ...
Read MoreHow to perform update in MySQL to disallow incrementing all the values above a specific value?
Let us first create a table −mysql> create table DemoTable -> ( -> Value int -> ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values(150); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(180); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+-------+ | Value ...
Read MoreWhat are the different types of MySQL GENERATED COLUMNS?
We have two types of MYSQL generated columns as follows −VIRTUAL GENERATED COLUMNAs the name suggests, this kind of generated column will not take any disk space. It can be generated with or without using the keyword ‘virtual’. To understand we are illustrating it in the following example −Examplemysql> Create table triangle(SideA DOUBLE, SideB DOUBLE, SideC DOUBLE AS (SQRT(SideA * SideB + SideB * SideB))); Query OK, 0 rows affected (0.44 sec) mysql> Describe Triangle; +-------+--------+------+-----+---------+-------------------+ | Field | Type | Null | Key | Default | Extra | +-------+--------+------+-----+---------+-------------------+ | SideA ...
Read MoreHow can we create a MySQL view by selecting some range of values from a base table?
As we know that MySQL BETWEEN operator can be used to select values from some range of values. We can use BETWEEN operator along with views to select some range of values from the base table. To understand this concept we are using the base table ‘student_info’ having the following data −mysql> Select * from Student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | ...
Read MoreHow can MySQL handle the errors during trigger execution?
Suppose if an error occurs during trigger execution then MySQL can handle it as follows −If a BEFORE trigger fails, the operation on the corresponding row is not performed.A BEFORE trigger is activated by the attempt to insert or modify the row, regardless of whether the attempt subsequently succeeds.An AFTER trigger is executed only if any BEFORE triggers and the row operation execute successfully.An error during either a BEFORE or AFTER trigger results in failure of the entire statement that caused trigger invocation.For transactional tables, failure of a statement should cause a rollback of all changes performed by the statement. ...
Read MoreHow MySQL manage the behavior of a transaction?
MySQL can manage the behavior of a transaction with the help of the following two modes −Autocommit OnIt is the default mode. In this mode, each MySQL statement (within a transaction or not) is considered as a complete transaction and committed by default when it finishes. It can be started by setting the session variable AUTOCOMMIT to 1 as follows −SET AUTOCOMMIT = 1 mysql> SET AUTOCOMMIT = 1; Query OK, 0 rows affected (0.07 sec)Autocommit OffIt is not the default mode. In this mode, the subsequent series of MySQL statements act like a transaction, and no activities are committed ...
Read MoreWhat MySQL returns if the first argument of INTERVAL() function is NULL?
MySQL returns -1 as output if the first argument of INTERVAL() function is NULL. Following example will demonstrate it −mysql> Select INTERVAL(NULL, 20, 32, 38, 40, 50, 55); +--------------------------------------+ | INTERVAL(NULL, 20, 32, 38, 40, 50, 55) | +--------------------------------------+ | -1 | +--------------------------------------+ 1 row in set (0.00 sec)It will return -1 even if any of the other arguments is NULL along ...
Read MoreWrite down the MySQL query which shows equality condition?
The binary equality operators compare their operands for strict equality or inequality. In MySQL, the equal-to-operator (=) returns 1 if both the operands have the same value otherwise returns 0. Following MySQL query show an equality condition −mysql> Select tender_value From estimated_cost WHERE id = 3;The above query shows an equality condition because the column id equates to the integer value.mysql> Select tender_value From estimated_cost1 WHERE Name_company = 'Chd Ltd.';The above query shows an equality condition because column Name_company equates to the string value.
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