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MySQL Articles
Page 295 of 355
Query with values prepended by ampersand works in Oracle but not in MySQL?
Ampersands work in Oracle. To work it in MySQL, use @ as shown in the following syntax −SET @yourVariableName1 = yourValue, @yourVariableName2 = yourValue, @yourVariableName3 =yourValue, .........N; insert into yourTableName values(@yourVariableName1, @yourVariableName2, @yourVariableName3, ........N);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table Student_Information -> ( -> StudentId int, -> StudentName varchar(100), -> StudentAge int, -> StudentMarks int, -> StudentCountryName varchar(10) -> ); Query OK, 0 rows affected (0.75 sec)Here is the query with values prepended by @. Insert some records ...
Read MoreVerify that MySQL SET FOREIGN KEY CHECKS is set to = 1?
You can verify SET FOREIGN KEY CHECKS is set to = 1 or not with the help of variable@@foreign_key_checks;The syntax is as follows −select @@foreign_key_checks;You can use SHOW VARIABLES command. The syntax is as follows −show variables like 'foreign%';Now you can implement both the syntaxes.Case 1 − Using variable @@foreign_key_checks.The query is as follows −mysql> SELECT @@foreign_key_checks; Here is the output −+----------------------+ | @@foreign_key_checks | +----------------------+ | 1 | +----------------------+ 1 row in set (0.00 sec)Case 2 − Using SHOW commandThe ...
Read MoreBulk change all entries for a particular field in MySQL?
Let us first create a demo table −mysql> create table BulkChangeDemo -> ( -> CustomerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> CustomerName varchar(20), -> isEducated boolean -> ); Query OK, 0 rows affected (1.47 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('Larry', true); Query OK, 1 row affected (0.09 sec) mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('John', false); Query OK, 1 row affected (0.16 sec) mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('Carol', false); Query OK, 1 row affected (0.25 sec) mysql> insert into BulkChangeDemo(CustomerName, ...
Read MoreMySQL index on column of int type?
Adding an index on column of int type is a good choice to run your query faster whenever your table has lots of records.If your table has less records then it is not a good choice to use index on column of int type.To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table indexOnIntColumnDemo -> ( -> UserId int, -> UserName varchar(20), -> UserAge int, -> INDEX(UserId) -> ); Query OK, 0 rows affected (0.85 sec)Now check the description of table −mysql> desc ...
Read MoreMySQL find/ replace string in fields?
To find/replace string in fields, the syntax is as follows −update yourTableName set yourColumnName =REPLACE(yourColumnName, yourOldValue, yourNewValue);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table FindReplaceDemo -> ( -> FileId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> FileDirectory text -> ); Query OK, 0 rows affected (0.92 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into FindReplaceDemo(FileDirectory) values('C://User//MySQL'); Query OK, 1 row affected (0.19 sec) mysql> insert into FindReplaceDemo(FileDirectory) values('D://WebsiteImage//image1.jpg'); Query OK, ...
Read MoreMySQL select accumulated (running sum) column?
To select accumulated column, let us first create a demo table. The query to create a table is as follows −mysql> create table accumulatedDemo -> ( -> Value int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into accumulatedDemo values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into accumulatedDemo values(15); Query OK, 1 row affected (0.09 sec) mysql> insert into accumulatedDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into accumulatedDemo values(25); Query OK, 1 row affected ...
Read MoreCheck replication type in MySQL?
To check replication type, you can use SHOW GLOBAL VARIABLES command. The syntax is as follows −SHOW GLOBAL VARIABLES LIKE 'binlog_format';The above syntax returns either ROW, MIXED or STATEMENT. The default resultant is ROW.Now you can implement the above syntax to check replication type. The query is as follows −mysql> SHOW GLOBAL VARIABLES LIKE 'binlog_format';Here is the output −+---------------+-------+ | Variable_name | Value | +---------------+-------+ | binlog_format | ROW | +---------------+-------+ 1 row in set (0.10 sec)Here is the query to switch from ROW to STATEMENT −mysql> SET GLOBAL binlog_format = 'STATEMENT'; Query OK, 0 rows affected (0.04 ...
Read MoreDeclare syntax error in MySQL Workbench?
The DECLARE syntax must between BEGIN and END. The syntax is as follows −BEGIN DECLARE yourVariableName1 dataType, DECLARE yourVariableName2 dataType, . . . . ENDHere is the query to avoid DECLARE syntax error in MySQL −mysql> DELIMITER // mysql> create procedure declare_Demo() -> BEGIN -> DECLARE Name varchar(100); -> SET Name: ='John'; -> SELECT Name; -> END -> // Query OK, 0 rows affected (0.17 sec) mysql> DELIMITER ;Call the stored procedure with the help of CALL command. The syntax is as follows −CALL yourStoredProcedureName();The query is as follows −mysql> call declare_Demo();The following is ...
Read MoreWhat does a "set+0" in a MySQL statement do?
The set+0 converts the set value to integer. Let us see an example by creating a table −mysql> create table SetZeroDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> TechnicalSkills set('C', 'Spring Framework /Hibernate', 'Python', 'Django Framework', 'Core Java') NOT NULL -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SetZeroDemo(TechnicalSkills) -> values('C, Spring Framework /Hibernate, Python, Django Framework, Core Java'); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement. The ...
Read MoreReserving MySQL auto-incremented IDs?
To reserve MySQL auto-incremented IDs, the syntax is as follows −START TRANSACTION; insert into yourTableName values(), (), (), (); ROLLBACK; SELECT LAST_INSERT_ID() INTO @anyVariableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table reservingAutoIncrementDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY -> ); Query OK, 0 rows affected (0.45 sec)Insert some records in the table using insert command. The query is as follows −mysql> START TRANSACTION; Query OK, 0 rows affected (0.00 sec) mysql> insert into reservingAutoIncrementDemo values(), (), (), (); Query ...
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