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MySQL Articles
Page 217 of 355
MySQL GROUP BY and CONCAT() to display distinct first and last name
Let us first create a table −mysql> create table DemoTable ( FirstName varchar(100), LastName varchar(100) ); Query OK, 0 rows affected (0.92 sec) mysql> alter table DemoTable add index(FirstName, LastName); Query OK, 0 rows affected (1.00 sec) Records: 0 Duplicates: 0 Warnings: 0Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam', 'Smith'); Query OK, 1 row affected (0.73 sec) mysql> insert into DemoTable values('Adam', 'Smith'); Query OK, 1 row affected (1.17 sec) mysql> insert into DemoTable values('John', 'Doe'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Carol', 'Taylor'); Query OK, ...
Read MoreSelect distinct names from two columns in MySQL and display the result in a single column
For this, use UNION. Let us first create a table −mysql> create table DemoTable ( Name1 varchar(100), Name2 varchar(100) ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert commandmysql> insert into DemoTable values('Adam', 'Bob'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Adam', 'Bob'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('David', 'Chris'); 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 −+-------+-------+ | Name1 | Name2 | +-------+-------+ | ...
Read MoreUpdate 'a' record with 'b' and 'b' with 'a' in a MySQL column (swap) with only 'a' and 'b' values?
For this, use a CASE statement. Let us first create a table −mysql> create table DemoTable ( Value char(1) ); Query OK, 0 rows affected (1.21 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('a'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('b'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('a'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values('a'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('b'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable ...
Read MoreCan we use INTERVAL keyword while inserting date records in a MySQL table?
Yes, we can use INTERVAL while inserting data records. Let us first create a table −mysql> create table DemoTable ( ArrivalTime datetime ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command. Here, we are using INTERVAL keyword for incrementing the date records while inserting −mysql> insert into DemoTable values(date_add(now(), interval 4 hour)); Query OK, 1 row affected (0.41 sec) mysql> insert into DemoTable values(date_add('2016-01-31 10:40:50', interval 2 hour)); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(date_add('2015-05-01 12:00:00', interval 1 hour)); Query OK, 1 row affected (0.25 sec) mysql> ...
Read MoreCan we use "year" as a column came in a MySQL Table?
Yes, you can give the year as a column name in MySQL table since it isn’t a reserved word. Let us first create a table −mysql> create table DemoTable ( Year int ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1995); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(2019); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(2016); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(2018); Query OK, 1 row affected (0.13 sec)Display all records from ...
Read MoreConcatenate rows on the basis of boolean values in another column with MySQL
To concatenate rows on the basis of boolean value in another column, use GROUP_CONCAT(). Let us first create a table. Here, we have set one of the columns “isValidUser” as BOOLEAN −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserMessage varchar(100), isValidUser boolean ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserMessage, isValidUser) values('Hi', true); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable(UserMessage, isValidUser) values('Hello', false); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable(UserMessage, isValidUser) values('Good', ...
Read MoreMySQL ORDER BY letters (not numbers) for column values comprising strings with numbers like '456 John Smith'
To ORDER BY letters, use ORDER BY SUBSTRING(). Let us first create a table −mysql> create table DemoTable ( Id varchar(100) ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('456 John Smith'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('897 Adam Smith'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('1009 Bob Smith'); 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 −+----------------+ | Id ...
Read MoreTwo ways to fetch maximum value from a MySQL column with numbers
To fetch the maximum value, use any of the below-given syntaxes −select max(yourColumnName) from yourTableName; OR select *from yourTableName order by yourColumnName desc limit 1;Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.84 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(45); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(87); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(56); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(77); Query OK, 1 row affected ...
Read MoreMySQL query for alphabetical search (ABC) with REGEXP?
For alphabetic search, use the REGEX in MySQL. Here, let’s say we are searching for records beginning with A, B or C. The syntax to use REGEXP for the same purpose is as follows −select *from yourTableName where yourColumnName REGEXP '^[ABC]';Let us first create a table −mysql> create table DemoTable ( Name varchar(100) ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Mike'); Query ...
Read MoreUse TRIM on all records in a MySQL table?
TRIM is used to remove leading and trailing spaces. Let us first create a table −mysql> create table DemoTable ( StudentName varchar(100) ); Query OK, 0 rows affected (0.64 sec)Insert some records in the table using insert command. Here, we have inserted records with leading and trailing whitespaces −mysql> insert into DemoTable values(' Adam Smith '); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(' David Miller '); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(' Chris Brown '); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(' Carol ...
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