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Found 6702 Articles for Database
4K+ Views
You cannot use EXCEPT in MySQL, instead use the NOT IN operator. Let us first create a table −mysql> create table DemoTable ( Number1 int ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(300); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select * from DemoTable;This will produce the following output −+---------+ | ... Read More
132 Views
Both pow() and power() are synonyms in MySQL. Following is the syntax −select pow(yourValue1, yourValue2); OR select power(yourValue1, yourValue2);Let us implement both the above syntaxes.Using POW()mysql> select POW(4, 3);This will produce the following output −+----------+ | POW(4, 3) | +----------+ | 64 | +----------+ 1 row in set (0.00 sec)Using POWER()mysql> select POWER(4, 3);This will produce the following output −+------------+ | POWER(4, 3) | +------------+ | 64 | +------------+ 1 row in set (0.00 sec)Let us implement the above syntax in a table −mysql> create table ... Read More
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Let us first create a table wherein we have a Primary Key CustomerId −mysql> create table DemoTable ( CustomerId int NOT NULL AUTO_INCREMENT, CustomerName varchar(20), CustomerAge int, CustomerCountryName varchar(100), PRIMARY KEY(CustomerId) ); Query OK, 0 rows affected (0.94 sec)Following is the query to get the primary key “column name” of a specific table in MySQL −mysql> SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME = 'DemoTable' AND CONSTRAINT_NAME = 'PRIMARY';This will produce the following output −+-------------+ | COLUMN_NAME | +-------------+ | CustomerId | +-------------+ 1 row in set, 2 warnings (0.12 sec)
307 Views
To convert MM/DD/YY to UNIX timestamp, you can use the below syntax −select UNIX_TIMESTAMP(str_to_date(yourColumnName, '%m/%d/%Y')) from yourTableName;Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, dateConvertToUnix varchar(100) ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(dateConvertToUnix) values('01/10/2001'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(dateConvertToUnix) values('03/31/2010'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(dateConvertToUnix) values('12/31/2016'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(dateConvertToUnix) values('04/27/2019'); Query OK, 1 ... Read More
174 Views
You can use substring() for fields in MySQL to get part of string. Following is the syntax −select substring(yourColumnName, yourStartingIndex, yourEndingIndex) from yourTableName;Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Title longtext ); Query OK, 0 rows affected (0.57 sec)Insert records in the table using insert command −mysql> insert into DemoTable(Title) values('MySQL is a relational database management system'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Title) values('MongoDB is a popular No SQL database'); Query OK, 1 row affected (0.18 sec)Display all records from ... Read More
265 Views
You cannot use ‘from’ as column name directly because ‘from’ is a reserved word in MySQL.If you want to still use it, then you need to use the backtick symbol.Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, `from` varchar(100), Name varchar(10) ); Query OK, 0 rows affected (0.92 sec)Insert records in the table using insert command −mysql> insert into DemoTable(`from`, Name) values('US', 'John'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(`from`, Name) values('UK', 'Carol'); Query OK, 1 row affected (0.14 sec) mysql> ... Read More
1K+ Views
First, you need to know how many columns are present in a table. Following is the syntax to know the column names −show columns from yourTableName;Following is the syntax to concatenate all columns −select concat(yourColumnName1, yourColumnName2, yourColumnName3, ........N) from yourTableName;Let us first create a table −mysql> create table DemoTable ( CustomerId int, CustomerName varchar(20), CustomerAge int ); Query OK, 0 rows affected (0.66 sec)Following is the query to know the exact column −mysql> show columns from DemoTable;This will produce the following output −+--------------+-------------+------+-----+---------+-------+ | Field | Type | Null ... Read More
1K+ Views
You can use aggregate function MAX() and MIN() for this.Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Number1 int, Number2 int ); Query OK, 0 rows affected (0.89 sec)Insert records in the table using insert command −mysql> insert into DemoTable(Number1, Number2) values(67, 45); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Number1, Number2) values(90, 40); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Number1, Number2) values(80, 43); Query OK, 1 row affected (0.48 sec)Display all records from the table using select ... Read More
131 Views
To modify an existing column’s data type, you can use MODIFY. Let us first create a table −mysql> create table DemoTable ( ClientId varchar(100), ClientName varchar(100), ClientAge int, ClientProjectDeadline timestamp, ClientCountryName varchar(100), isMarried boolean, ClientNumber bigint ); Query OK, 0 rows affected (0.70 sec)Check the description of table −mysql> desc DemoTable;This will produce the following output −+-----------------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------------------+--------------+------+-----+---------+-------+ | ClientId ... Read More
91 Views
You can use UPDATE with DATE_ADD() to update all dates. Let us first create a table −mysql> create table DemoTable ( ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientProjectDueDate date ); Query OK, 0 rows affected (1.19 sec)Insert records in the table using insert command −mysql> insert into DemoTable(ClientProjectDueDate) values('2018-01-21'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(ClientProjectDueDate) values('2019-03-25'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(ClientProjectDueDate) values('2013-11-01'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(ClientProjectDueDate) values('2015-06-14'); Query OK, 1 row affected (0.23 sec)Display all records from ... Read More