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Found 6705 Articles for Database

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To add 1 day, use date_add() function. Adding a day to datetime in MySQL gives the next day. The following is the syntax −SELECT DATE_ADD('Any date’', INTERVAL 1 DAY) AS AliasName;Now, I am applying the above query to add a day with date in MySQL. The query is as follows −mysql> SELECT DATE_ADD('2018-10-08', INTERVAL 1 DAY) AS NextDay; After executing the above query, we will get the following output −+------------+ | NextDay | +------------+ | 2018-10-09 | +------------+ 1 row in set (0.00 sec)Therefore, in this sample output, I am adding a day with current date

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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 More

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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 More

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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 More

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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 More

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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 More

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In MySQL, schema is synonymous with database. As the query is written to create the database, similarly the query can be written to create the schema.Logical structure can be used by the schema to store data while memory component can be used by the database to store data. Also, a schema is collection of tables while a database is a collection of schema.To clarify this concept, a database and a schema are created. The steps for this are as follows −First, a database is created with the following syntax −create database yourDatabaseName;The above syntax is used in a query as ... Read More

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Before stopping a running query of MySQL, first we need to see how many processes are running with the help of show command.The query for that is given as follows −mysql> show processlist;After executing the above query, we will get the output with some id’s. This is given as follows −+----+-----------------+-----------------+----------+---------+-------+------------------------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+-----------------+-----------------+----------+---------+-------+------------------------+------------------+ | 4 | event_scheduler | localhost | NULL | Daemon | 71034 | Waiting on empty queue | NULL | | 8 | Manish | localhost:53496 | business | Query | ... Read More

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Non ASCII characters are characters such as the pound symbol(£), trademark symbol, plusminus symbol etc. To find the non-ASCII characters from the table, the following steps are required −First a table is created with the help of the create command which is given as follows −mysql> CREATE table NonASciiDemo -> ( -> NonAScii varchar(100) -> ); Query OK, 0 rows affected (0.61 sec)After that the records are inserted into the table with the help of the insert command which is as follows −mysql> INSERT into NonASciiDemo values('-, -'); Query OK, 1 row affected (0.18 sec) mysql> INSERT into NonASciiDemo ... Read More

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In innoDB, NULL occupies less space as compared to empty string. Also, the NULL length is null while length of the empty string is 0.To understand this, a table is created with the help of create command which is given as follows −mysql> CREATE table DemoEmptyAndNULL -> ( -> Message varchar(100) -> ); Query OK, 0 rows affected (0.49 sec)After creating the table successfully, an empty record is inserted into the table with the help of insert command which is as follows −mysql> INSERT into DemoEmptyAndNULL values(' '); Query OK, 1 row affected (0.17 sec)After inserting the record, we can ... Read More