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MySQL Articles
Page 239 of 355
How can I install or enable innoDB in MySQL?
In order to enable innoDB in MySQ, you need to work around my.ini file. However, in MySQL version 8, the default storage engine is innoDB. Check the same from my.ini file −You can even set this at the time of table creation −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(100), StudentLastName varchar(100), StudentAge int ) ENGINE=InnoDB; Query OK, 0 rows affected (1.66 sec)Let us now run a query to check the engine type of specific table −mysql> select table_name, engine from information_schema.tables where table_name="DemoTable";This will produce the following ...
Read MoreGet at least x number of rows in MySQL?
To get at least x number of rows, you need to use the LIMIT clause. Following is the syntax −select *from yourTableName order by yourColumnName DESC limit yourXNumberOfRows;Let us first create a table −mysql> create table DemoTable ( EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, EmployeeName varchar(100) ); Query OK, 0 rows affected (0.76 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(EmployeeName) values('Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(EmployeeName) values('David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(EmployeeName) values('Bob'); Query OK, 1 row affected (0.51 sec) ...
Read MoreWhich is faster, a MySQL CASE statement or a PHP if statement?
The MySQL CASE statement is faster in comparison to PHP if statement. The PHP if statement takes too much time because it loads data and then process while CASE statement does not.Let us first create a table and work around an example of MySQL CASE statement −mysql> create table DemoTable (Value int); Query OK, 0 rows affected (0.70 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable values(500); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(1000); Query OK, 1 row ...
Read MoreMySQL query to select records approaching in next 12 hours?
For this, you can use INTERVAL 12 hour using DATE_ADD(). Let us first create a table −mysql> create table DemoTable (DueDateTime datetime); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-07-12 10:50:30'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable values('2019-07-12 22:02:00'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('2019-07-12 11:12:10'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2019-07-12 09:02:00'); Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement −mysql> select *from ...
Read MoreHow to generate 5 random numbers in MySQL stored procedure?
To generate random numbers, use the ORDER BY RAND() function in MySQL. Let us first create a table −mysql> create table DemoTable (Value int); Query OK, 0 rows affected (0.76 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(89); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(98); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values(78); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(75); Query OK, 1 row affected (0.14 sec) mysql> ...
Read MoreHow to set different auto-increment ids for two tables with a user-defined variable?
For this, you can use LAST_INSERT_ID(). Let us first create a table. Here, we have set the auto_increment id to StudentId column −mysql> create table DemoTable1 (StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(null); Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following output −+-----------+ | StudentId | +-----------+ | 1 | +-----------+ 1 row in set (0.00 sec)Following is the query to ...
Read MoreIs MySQL's SLEEP() function a busy-wait? How to implement it?
No, MySQL sleep function is not busy-wait. Let us first create a table and implement the SLEEP() function −mysql> create table DemoTable(FirstName varchar(100)); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Adam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Bob'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Robert'); Query OK, 1 row affected (0.16 sec)Display all records ...
Read MoreMySQL order by field using CASE Statement
To order by field, use CASE statement. Let us first create a table −mysql> create table DemoTable(StudentId varchar(100)); Query OK, 0 rows affected (1.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('STU-980'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values('STU-1029'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable values('STU-189'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('STU-890'); Query OK, 1 row affected (0.38 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-----------+ | ...
Read MoreGetting count of two different sets of rows in a table and then dividing them in MySQL
For this, use count(*) and the divide the count of two different sets of rows. Let us first create a table −mysql> create table DemoTable(isMarried tinyint(1)); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.17 ...
Read MoreCopy all rows of a table to another table in MySQL?
To copy all rows of a table to another table, use the below syntax −insert into yourTableName2(yourColumnName1, ...N) select yourColumnName1, ..N from yourTableName1;Let us first create a table −mysql> create table DemoTable1(FirstName varchar(100)); Query OK, 0 rows affected (1.11 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values('John'); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable1 values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1 values('Bob'); Query OK, 1 row affected (0.40 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following ...
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