Found 4378 Articles for MySQL

What does % stand for in host column and how to change user's password?

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

202 Views

The localhost means you can access from same machine while from % the remote host access is possible. The syntax is as follows to change the user password.SET PASSWORD FOR 'yourUserName'@'localhost' ='yourPassword';First check the user and host from MySQL.user table. The query is as follows −mysql> select user, host from MySQL.user;Here is the output −+------------------+-----------+ | user             | host      | +------------------+-----------+ | Bob              | %       | | Manish | % ... Read More

Select timestamp as date string in MySQL?

Samual Sam
Updated on 30-Jul-2019 22:30:25

212 Views

To select timestamp as date string in MySQL, the syntax is as follows −select FROM_UNIXTIME(yourColumnName, '%Y-%m-%d %H:%i:%s') from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table select_timestampDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ArrivalDateTime int    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into select_timestampDemo(ArrivalDateTime) values(1546499730); Query OK, 1 row affected (0.18 sec) mysql> insert into select_timestampDemo(ArrivalDateTime) values(1546210820); Query OK, 1 ... Read More

Correctly implement the AND condition in MySQL

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

66 Views

To implement AND condition, the syntax is as follows −select *from yourTableName where yourColumnName1 = yourValue1 AND yourColumnName2 = yourValue2;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table MySQLANDConditionDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(100),    -> Age int    -> ); Query OK, 0 rows affected (0.80 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into MySQLANDConditionDemo(Name, Age) values('Larry', 23); Query OK, 1 row affected (0.11 sec) mysql> ... Read More

How to insert a row into a table that has only a single autoincrement column?

Samual Sam
Updated on 30-Jul-2019 22:30:25

339 Views

You can easily insert a row into a table that has only a single auto increment column. The syntax is as follows −insert into yourTableName set yourColumnName =NULL;You can use the below syntax −insert into yourTableName values(NULL);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table singleAutoIncrementColumnDemo    -> (    -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into singleAutoIncrementColumnDemo set UserId ... Read More

How to fix poor performance of INFORMATION_SCHEMA.key_column_usage in MySQL?

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

128 Views

You can use GLOBAL variable as shown below −SET global innodb_stats_on_metadata =0;After including the above syntax, the INFORMATION_SCHEMA.key_column_usage will take less time and that would improve the performance.The query is as follows −mysql> set global innodb_stats_on_metadata =0; Query OK, 0 rows affected (0.00 sec) mysql> SELECT REFERENCED_TABLE_NAME,TABLE_NAME,COLUMN_NAME,CONSTRAINT_SCHEMA -> FROM INFORMATION_SCHEMA.key_column_usage;The following is the output −It returns 674 rows in 0.28 seconds.

Ignoring the year in MySQL Query with date range?

Samual Sam
Updated on 30-Jul-2019 22:30:25

497 Views

To ignore the year with date range, use the DATE_FORMAT() with the between clause. Let us first create a demo table. The query to create a table is as follows −mysql> create table igonreYearDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ShippingDate date    -> ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into igonreYearDemo(ShippingDate) values('2016-01-31'); Query OK, 1 row affected (0.16 sec) mysql> insert into igonreYearDemo(ShippingDate) values('2018-01-31'); Query OK, 1 row affected (0.13 sec) mysql> insert into ... Read More

Get the number of days between current date and date field?

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

102 Views

To get the number of days between current date and date field, the syntax is as follows −SELECT DATEDIFF(CURDATE(), STR_TO_DATE(yourColumnName, '%d-%m-%Y')) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table DateDifferenceDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ArrivalDate varchar(100)    -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into DateDifferenceDemo(ArrivalDate) values('12-10-2011'); Query OK, 1 row affected (0.14 sec) mysql> insert ... Read More

Reserving MySQL auto-incremented IDs?

Samual Sam
Updated on 30-Jul-2019 22:30:25

223 Views

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 ... Read More

What does a “set+0” in a MySQL statement do?

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

57 Views

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 More

Declare syntax error in MySQL Workbench?

karthikeya Boyini
Updated on 30-Jul-2019 22:30:25

2K+ Views

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 More

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