Found 4378 Articles for MySQL

Remove all except the first character of a string in MySQL?

Sharon Christine
Updated on 30-Jun-2020 13:24:00

212 Views

For this, use the LEFT() method, which returns a specified number of characters from the left of the string.Let us first create a table −mysql> create table DemoTable    -> (    -> FirstName varchar(100)    -> ); Query OK, 0 rows affected (0.96 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Mike'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> ... Read More

MySQL query with two boolean conditions to extract date based on hour?

Sharon Christine
Updated on 30-Jun-2020 13:24:50

105 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> AdmissionDate datetime    -> ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-10 10:45:10'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable values('2019-02-12 20:50:00'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2019-02-12 16:10:19'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+---------------------+ | AdmissionDate ... Read More

How to remove all instances of a specific character from a column in MySQL?

Kumar Varma
Updated on 30-Jun-2020 13:26:05

834 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> FirstName varchar(100)    -> ); Query OK, 0 rows affected (0.41 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam^^^'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('^^^^^^^^Carol'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Robert^^^^^^'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+---------------+ | FirstName     | +---------------+ | Adam^^^   ... Read More

How to create and fill a new column in an already created MySQL table?

Rama Giri
Updated on 30-Jun-2020 13:27:16

1K+ Views

Let us first create a table −mysql> create table DemoTable    -> (    -> Value1 int,    -> Value2 int    -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(20, 30); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+--------+--------+ | Value1 | Value2 | +--------+--------+ |     10 |   10 | ... Read More

How to get total occurrences of a value within its own MySQL query?

Kumar Varma
Updated on 30-Jun-2020 13:29:19

143 Views

For this, you can use subquery. Let us first create a table −mysql> create table DemoTable    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.36 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(30); Query OK, ... Read More

Get the number of rows in a particular table with MySQL

Rama Giri
Updated on 30-Jun-2020 13:30:38

112 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> LastName varchar(100)    -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Miller'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Taylor'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Brown'); Query OK, 1 row affected (0.29 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce ... Read More

Query MySQL with unicode char code?

Kumar Varma
Updated on 30-Jun-2020 13:33:31

345 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(0x41); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(0x30); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(0x61); Query OK, 1 row affected (0.27 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+-------+ | Value | +-------+ |    65 | | ... Read More

How to get the seed value of an identity column in MySQL?

Rama Giri
Updated on 30-Jun-2020 13:09:13

477 Views

For this, you can use SHOW VARIABLES command −mysql> SHOW VARIABLES LIKE 'auto_inc%';OutputThis will produce the following output −+--------------------------+-------+ | Variable_name            | Value | +--------------------------+-------+ | auto_increment_increment | 1     | | auto_increment_offset    | 1     | +--------------------------+-------+ 2 rows in set (0.95 sec)You can control over AUTO_INCREMENT outside.Let us first create a table −mysql> create table DemoTable    -> (    -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY    -> ); Query OK, 0 rows affected (0.94 sec)Insert some records in the table using insert command −mysql> insert into DemoTable ... Read More

Select the topmost record from a table ordered by desc on the basis of ID?

Kumar Varma
Updated on 30-Jun-2020 13:10:20

44 Views

For this, use ORDER BY DESC with LIMIT 1. Let us first create table −mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> UserName varchar(100),    -> UserMessage text    -> ); Query OK, 0 rows affected (1.17 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName, UserMessage) values('Adam', 'Hi'); Query OK, 1 row affected (0.92 sec) mysql> insert into DemoTable(UserName, UserMessage) values('Chris', 'Awesome'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable(UserName, UserMessage) values('Robert', 'Nice'); Query OK, 1 row affected (0.65 sec) ... Read More

Display records ignoring NULL in MySQL

Rama Giri
Updated on 30-Jun-2020 13:11:10

106 Views

Use IS NOT NULL to display only NOT NULL records. Let us first create a table −mysql> create table DemoTable    -> (    -> FirstName varchar(100)    -> ); Query OK, 0 rows affected (3.01 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.44 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.58 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.20 sec) mysql> insert into ... Read More

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