webseite:mysql:basic
MySQL Basics
Data Definition Language (DDL)
CREATE | create new objects in db |
ALTER | alters / change the structure of the db |
DROP | delete objects from the db |
Data Manipulation Language (DML)
SELECT | retrieve data from db |
INSERT | insert data into a table |
UPDATE | updates existing data in a table |
DELETE | deletes all records from a table, space for the records remain |
Basics
Code | Function |
CREATE TABLE Personal (Lastname CHAR(50) Firstname CHAR(50) Rank VARCHAR(30) Salary (INT)); | Create table |
INSERT INTO Personal (Lastname, Firstname) VALUES ('Doe', 'John') | Insert in table |
UPDATE Personal SET Salary=3200 WHERE Lastname = “Doe”; | Change the salary of a person with the lastname Doe |
DELETE FROM Personal WHERE Lastname = “Doe” AND Firstname = “John”; | Remove John Doe |
DROP TABLE Personal; | Remove table |
ALTER TABLE Personal ADD Gender CHAR (1); | Add a new column Gender |
SELECT Lastname, Firstname FROM Personal ORDER BY Lastname; | Order the output by lastname |
SELECT Rank FROM Personal GROUP BY Rank; | Shows the ranks grouped |
SELECT COUNT(*) FROM table; | Counts all entries |
SELECT * FROM table WHERE field LIKE '%text%'; | Select all columns for a field with the value “text” |
SELECT a.name, a.age, b.address FROM table1 a, table2 b WHERE a.id = b.id; | You can use this instead of inner join |
Code examples
Code | Function |
SELECT * FROM Table WHERE Cell LIKE 'test' | select all rows in Table where Cell contains 'test' |
SELECT IdX FROM Table WHERE Cell LIKE '$Var' | select IdX from Table where Cell contains variable Var |
SELECT * FROM Table ORDER BY IdX DESC LIMIT 0,10 | select all rows limited by 10, order everything by IdX and from newest top to oldest bottom |
SELECT * FROM Table WHERE Cell LIKE '%$Var%' | select all rows from table where cell is almost like variable Var |
UPDATE `DB`.`Table` SET `Cell1` = '$Var1' WHERE `Table`.`Cell2`='$Var2' | update Table Cell2 to Var2 where Cell1 is Var1 |
INSERT INTO Table (Cell1, Cell2) VALUES ('Text', '$Var1') | add new row into Table with cell1 as Text and Cell2 as Var1 |
webseite/mysql/basic.txt · Last modified: 2018/12/20 17:40 by lunetikk
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