Found 6702 Articles for Database

What is the difference between BIT and TINYINT in MySQL?

Arjun Thakur
Updated on 30-Jul-2019 22:30:23

613 Views

BIT can be used to store the value of 1 bit. It could be 0 or 1. We cannot store, for example 2 with data type BIT. If we try to insert 2 with BIT data type, MySQL raises an error. TINYINT can be used to store value of 8 bits. The maximum value we can store is 127.We cannot store, for example 987 with 8 bit value. If we try to insert 987 with TINYINT data type, MySQL raises an error. Let us work it through MySQL version 8.0.12. To check the version installed on your system. mysql> ... Read More

How to select last 10 rows from MySQL?

Chandu yadav
Updated on 12-Sep-2023 01:58:16

33K+ Views

To select last 10 rows from MySQL, we can use a subquery with SELECT statement and Limit concept. The following is an example. Creating a table. mysql> create table Last10RecordsDemo -> ( -> id int, -> name varchar(100) -> ); Query OK, 0 rows affected (0.75 sec) Inserting records into the table. mysql> insert into Last10RecordsDemo values(1, 'John'), (2, 'Carol'), (3, 'Bob'), (4, 'Sam'), (5, 'David'), (6, 'Taylor'); Query OK, 6 rows affected (0.12 sec) Records: 6 Duplicates: 0 Warnings: 0 mysql> insert into Last10RecordsDemo ... Read More

What is the maximum length of a table name in MySQL?

George John
Updated on 30-Jul-2019 22:30:23

2K+ Views

The maximum length of a table name is 64 characters long according to MySQl version 8.0.12. Check your installed MySQL version. mysql> select version(); The following is the output. +-----------+ | version() | +-----------+ | 8.0.12 | +-----------+ 1 row in set (0.03 sec) We can check the maximum length of the table name at the time of creating it. If we give more than 64 characters, then it will not create a table and an error is thrown. Creating a table which has more than 64 characters of table name. mysql> ... Read More

How to convert timestamp to datetime in MySQL?

Ankith Reddy
Updated on 30-Jul-2019 22:30:23

5K+ Views

We can convert the timestamp to date time with the help of FROM_UNIXTIME() function. Let us see an example. First, we will create a table with column of int type. Then we convert it to timestamp and again into date time. Creating a table with integer type. mysql> create table TimestamptoDateDemo -> ( -> YourTimeStamp int(11) -> ); Query OK, 0 rows affected (0.57 sec) Inserting records into the table. mysql> insert into TimestamptoDateDemo values(1389453221); Query OK, 1 row affected (0.23 sec) To display all the ... Read More

What are the differences between the BLOB and TEXT datatypes in MySQL?

Chandu yadav
Updated on 30-Jul-2019 22:30:23

2K+ Views

BLOB stands for Binary Large Objects and as its name suggests, it can be used for storing binary data while TEXT is used for storing large number of strings. BLOB can be used to store binary data that means we can store pictures, videos, sounds and programs also. For example, the following image can be stored into BLOB because the image has binary data. BLOB values behave like byte string and BLOB does not have a character set. Therefore, comparison and sorting is fully dependent upon numeric values of bytes. TEXT values behave like non-binary string or character string. ... Read More

How to find the number of columns in a MySQL table?

Ankith Reddy
Updated on 30-Jul-2019 22:30:23

14K+ Views

To find the number of columns in a MySQL table, use the count(*) function with information_schema.columns and the WHERE clause. Let us see an example. Creating a table. mysql> create table NumberOfColumns -> ( -> id int, -> FirstName varchar(100), -> LastName varchar(100), -> Age int, -> Address varchar(100) -> ); Query OK, 0 rows affected (0.70 sec) Inserting records into table. mysql> insert into NumberOfColumns values(1, 'Shane', 'Watson', 36, 'Australia'); Query OK, 1 row affected ... Read More

Why do integers in database row tuple have an 'L' suffix in MySQL?

Arjun Thakur
Updated on 30-Jul-2019 22:30:23

238 Views

The ‘L’ suffix concept in MySQL can be related with Python. In Python 2, the long integer literal is suffixed with L or l, but int and long have been binded into int in version 3. Therefore, there is no need for L or l. Adding large numbers in Python Version 3.7 (Python 3), without using any suffix. Here, if we suffix L or l, Python 3 gives an error. However, Python Version 2 suffixed with L or l will not give an error. The following is the output with no error. Hence, Python int is ... Read More

How to remove all non-alphanumeric characters from a string in MySQL?

Chandu yadav
Updated on 30-Jul-2019 22:30:23

2K+ Views

Non-alphanumeric characters are as follows − @, !, #, &, (), ?, / There is no inbuilt function to remove non-alphanumeric characters from a string in MySQL. Therefore, we create a function which removes all non-alphanumeric characters. The function declaration and definition is as follows. mysql> delimiter // mysql> CREATE FUNCTION RemoveNonAlphaNumeric( s CHAR(255) ) RETURNS CHAR(255) DETERMINISTIC -> BEGIN -> DECLARE var1, length SMALLINT DEFAULT 1; -> DECLARE result CHAR(255) DEFAULT ''; -> DECLARE ch CHAR(1); ... Read More

MySQL select query to select rows from a table that are not in another table?

Chandu yadav
Updated on 30-Jul-2019 22:30:23

2K+ Views

For our example, we will create two tables and apply Natural Left Join to get the rows from a table not present in the second table. Creating the first table. mysql> create table FirstTableDemo -> ( -> id int, -> name varchar(100) -> ); Query OK, 0 rows affected (0.48 sec) Inserting records into first table. mysql> insert into FirstTableDemo values(1, 'Bob'), (2, 'John'), (3, 'Carol'); Query OK, 3 rows affected (0.13 sec) Records: 3 Duplicates: 0 Warnings: 0 To display all ... Read More

How to get the next auto-increment id in MySQL?

Arjun Thakur
Updated on 14-Sep-2023 01:25:33

29K+ Views

MySQL has the AUTO_INCREMENT keyword to perform auto-increment. The starting value for AUTO_INCREMENT is 1, which is the default. It will get increment by 1 for each new record. To get the next auto increment id in MySQL, we can use the function last_insert_id() from MySQL or auto_increment with SELECT. Creating a table, with "d" as auto-increment. mysql> create table NextIdDemo -> ( -> id int auto_increment, -> primary key(id) -> ); Query OK, 0 rows affected (1.31 sec) Inserting records into the table. mysql> insert into NextIdDemo ... Read More

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