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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to display all the tables in MySQL with a storage engine?
We can display all the tables with the help of the WHERE clause. The syntax for that is as follows −SELECT table_name FROM INFORMATION_SCHEMA.TABLES WHERE engine = 'InnoDB';Now, the above syntax is applied to the given query −mysql> SELECT * from INFORMATION_SCHEMA.TABLES WHERE engine = 'InnoDB';The following is the output obtained −+---------------+--------------+---------------------------+------------+--------+---------+------------+------------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+---------------------------------------+-----------------------------------------+ | TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | TABLE_TYPE | ENGINE | VERSION | ROW_FORMAT | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | MAX_DATA_LENGTH | INDEX_LENGTH | DATA_FREE | AUTO_INCREMENT | CREATE_TIME | UPDATE_TIME | CHECK_TIME | TABLE_COLLATION | CHECKSUM | CREATE_OPTIONS | TABLE_COMMENT | +---------------+--------------+---------------------------+------------+--------+---------+------------+------------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+---------------------------------------+-----------------------------------------+ | def | mysql ...
Read MorePagination using MySQL LIMIT, OFFSET?
Firstly, we need to create a table with some records, then we will use pagination with the help of limit and offset.Creating a table with the help of CREATE command. The query is as follows −mysql> CREATE table limitoffsetDemo -> ( -> id int, -> FisrtName varchar(200) -> ); Query OK, 0 rows affected (0.45 sec)After creating a table, we will insert records with the help of INSERT command.Inserting recordsmysql> INSERT into limitoffsetDemo values(1, 'John'); Query OK, 1 row affected (0.11 sec) mysql> INSERT into limitoffsetDemo values(2, 'Bob'); Query OK, 1 row affected (0.16 sec) mysql> INSERT into ...
Read MoreHow to use NULL in MySQL SELECT statement?
In MySQL, the length of NULL is 0. Here, we will see how NULL can be used with SELECT statement. Let us create a table with the help of CREATE command −Creating a table −mysql> CREATE table NullWIthSelect -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (0.62 sec)Above, I have created a table successfully. Now I will insert some records with the help of INSERT command −Inserting records −mysql> INSERT into NullWIthSelect values('John'); Query OK, 1 row affected (0.16 sec) mysql> INSERT into NullWIthSelect values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> INSERT ...
Read MoreHow do I set the timezone of MySQL?
To know the current time, we can use the now() function with SELECT statement. The query is as follows −mysql> SELECT now();After executing the above query, we will get the current time. The following is the output −+---------------------+ | now() | +---------------------+ | 2018-10-06 12:57:25 | +---------------------+ 1 row in set (0.02 sec)To set the time zone, we can use the command SET. The syntax is as follows −mysql> SET time_zone = "Some value"; Now I am applying the above query to set the time zone. ...
Read MoreHow do I get the current AUTO_INCREMENT value for a table in MySQL?
To know the current auto_increment value, we can use the last_insert_id() function. Firstly, we will create a table with the help of INSERT command.Creating a table −mysql> CREATE table AutoIncrement -> ( -> IdAuto int auto_increment, -> primary key(IdAuto) -> ); Query OK, 0 rows affected (0.59 sec)After creating a table, we will insert the records with the help of INSERT command. Inserting records −mysql> INSERT into AutoIncrement values(); Query OK, 1 row affected (0.48 sec) mysql> INSERT into AutoIncrement values(); Query OK, 1 row affected (0.17 sec) mysql> INSERT into AutoIncrement values(); Query OK, 1 row affected ...
Read MoreWhat is unsigned in MySQL?
Unsigned allows us to enter positive value; you cannot give any negative number. Let us create a table to understand unsigned in MySQL. To create a table, we will use the CREATE command.Let us create a table −mysql> CREATE table UnsignedDemo -> ( -> id int unsigned -> ); Query OK, 0 rows affected (0.61 sec)After that I will insert only positive values. Let us insert some records −mysql> INSERT into UnsignedDemo values(124); Query OK, 1 row affected (0.09 sec) mysql> INSERT into UnsignedDemo values(78967); Query OK, 1 row affected (0.14 sec)I am displaying all the records with the ...
Read MoreHow to enable MySQL Query Log?
To enable query log, use the command SET global. You cannot use set general_log in MySQL version 8.0.12 version. If you are using version 8.0.12, then you will get the below given error. Here, we are trying to set general_log to see what error will come −mysql> SET general_log = 1;The following is the output −ERROR 1229 (HY000): Variable 'general_log' is a GLOBAL variable and should be set with SET GLOBAL Now, we will use the global command with general_log. The query is as follows −mysql> SET global general_log = 1; Query OK, 0 rows affected (0.10 sec)To check it ...
Read MoreSELECT DISTINCT vs GROUP BY in MySQL?
SELECT DISTINCT can be used to give distinct values. Use it to remove duplicate records and it can be used with aggregate function as well. For example: MAX, AVG etc. This can be applied on a single column.Now, I am creating a table to use SELECT DISTINCT for a column. Creating a table with the help of CREATE command −mysql> CREATE TABLE DistinctDemo -> ( -> id int, -> name varchar(100) -> ); Query OK, 0 rows affected (0.64 sec)Inserting records −mysql> INSERT into DistinctDemo values(1, 'John'); Query OK, 1 row affected (0.17 sec) mysql> INSERT into DistinctDemo values(2, ...
Read MoreHow can I search (case-insensitive) in a column using LIKE wildcard?
We can do this with the help of lower() with column name. Firstly, we will create a table with the help of CREATE command.Creating a table −mysql> CREATE table InCaseSensDemo -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (0.50 sec)Inserting records into the table with the help of INSERT command −mysql> INSERT into InCaseSensDemo values('JOhN'); Query OK, 1 row affected (0.11 sec) mysql> INSERT into InCaseSensDemo values('bob'); Query OK, 1 row affected (0.21 sec) mysql> INSERT into InCaseSensDemo values('BoB'); Query OK, 1 row affected (0.13 sec) mysql> INSERT into InCaseSensDemo values('Bob'); Query OK, ...
Read MoreHow to make SQL case sensitive string comparison in MySQL?
Firstly, we will create a table with the help of CREATE command.Creating a table −mysql> CREATE table InCaseSensDemo -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (0.50 sec)Inserting records into the table with the help of INSERT command −mysql> INSERT into InCaseSensDemo values('JOhN'); Query OK, 1 row affected (0.11 sec) mysql> INSERT into InCaseSensDemo values('bob'); Query OK, 1 row affected (0.21 sec) mysql> INSERT into InCaseSensDemo values('BoB'); Query OK, 1 row affected (0.13 sec) mysql> INSERT into InCaseSensDemo values('Bob'); Query OK, 1 row affected (0.18 sec)Displaying all the records with the help of ...
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