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Database Articles
Page 224 of 547
Search text containing a new line in MySQL?
You can use REGEXP. Let us first create a table −mysql> create table DemoTable ( Name varchar(100) ); Query OK, 0 rows affected (1.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('JohnSmith'); Query OK, 1 row affected (0.73 sec) mysql> insert into DemoTable values('John Doe'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('DavidMiller'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable values('Carol Taylor'); Query OK, 1 row affected (0.27 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following ...
Read MoreMySQL query to count records that begin with specific letters
Let us first create a table −mysql> create table DemoTable775 ( FirstName varchar(100) ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command −mysql> insert into DemoTable775 values('Adam') ; Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable775 values('Carol'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable775 values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable775 values('Sam'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable775 values('Adan'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select ...
Read MoreORDERBY word in MySQL?
To order by word in MySQL, you need to use ORDER BY FIELD(). Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentFavouriteSubject varchar(100) ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentFirstName, StudentFavouriteSubject) values('Larry', 'Java'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(StudentFirstName, StudentFavouriteSubject) values('Sam', 'C'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(StudentFirstName, StudentFavouriteSubject) values('Bob', 'MongoDB'); Query OK, 1 row affected (0.17 sec) mysql> ...
Read MoreDifference Between MySql <> NULL and IS NOT NULL?
If you compare the operator with NULL value then you will get NULL value always and no result.Let us see some examples for comparison −mysql> select 10 NULL; +------------+ | 10 NULL | +------------+ | NULL | +------------+ 1 row in set (0.00 sec) mysql> select NULL NULL; +--------------+ | NULL NULL | +--------------+ | NULL | +--------------+ 1 row in set (0.00 sec) mysql> select 'Chris' NULL; +-----------------+ | 'Chris' NULL | +-----------------+ | NULL | +-----------------+ 1 row in ...
Read MoreDisplay MySQL histogram with negative values?
For negative values, use reverse() along with concat(). Let us first create a table −mysql> create table DemoTable632 ( histogramId int NOT NULL AUTO_INCREMENT PRIMARY KEY, histogramValue int, histogramImage text ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command −mysql> insert into DemoTable632(histogramValue) values(2); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable632(histogramValue) values(3); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable632(histogramValue) values(-6); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable632(histogramValue) values(-5); Query OK, 1 row affected (0.13 sec)Display all records from the table ...
Read MoreCount occurrences of known distinct values in MySQL
For this, you can use aggregate function SUM(). Let us first create a table −mysql> create table DemoTable636 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(100) ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable636(StudentFirstName) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable636(StudentFirstName) values('Robert'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable636(StudentFirstName) values('Robert'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable636(StudentFirstName) values('Sam'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable636(StudentFirstName) values('Mike'); Query OK, ...
Read MoreHow can I display all databases in MySQL and for each database show all tables?
For this, you can use INFORMATION_SCHEMA. Following is the syntax −select my_schema.SCHEMA_NAME, group_concat(tbl.TABLE_NAME) from information_schema.SCHEMATA my_schema left join information_schema.TABLES tbl on my_schema.SCHEMA_NAME=tbl.TABLE_SCHEMA group by my_schema.SCHEMA_NAME;Let us implement the above syntax in order to show all databases in MySQL and for each database −mysql> select my_schema.SCHEMA_NAME, group_concat(tbl.TABLE_NAME) from information_schema.SCHEMATA my_schema left join information_schema.TABLES tbl on my_schema.SCHEMA_NAME=tbl.TABLE_SCHEMA group by my_schema.SCHEMA_NAME;This will produce the following output −+---------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | SCHEMA_NAME | group_concat(tbl.TABLE_NAME) ...
Read MoreComma separated argument applicable for IN operator in MySQL?
Use FIND_IN_SET() for command separated argument. Let us first create a table −mysql> create table DemoTable604 (Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Title varchar(100)); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable604(Title) values('MySQL'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable604(Title) values('C++'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable604(Title) values('MongoDB'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable604(Title) values('Java'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable604;This ...
Read MorePurpose of using CHANGE command in MySQL?
The CHANGE command in MySQL is used to rename column name. Let us first create a table −mysql> create table DemoTable796 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(100), StudentAge int ); Query OK, 0 rows affected (0.56 sec)Let us check the description of table −mysql> desc DemoTable796;This will produce the following output −+------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | StudentId | int(11) | NO | PRI | NULL | auto_increment | | Name ...
Read MoreHow to get the count of a specific value in a column with MySQL?
Let us first create a table −mysql> create table DemoTable ( Id int, Name varchar(100) ); Query OK, 0 rows affected (1.40 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'John'); Query OK, 1 row affected (0.44 sec) mysql> insert into DemoTable values(101, 'Chris'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(102, 'Chris'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(103, 'Chris'); Query OK, 1 row affected (1.05 sec) mysql> insert into DemoTable values(104, 'David'); Query OK, 1 ...
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