SQL

Question	Answer
SQL	BY SAM - WRIGHT
SELECT	USED TO SELETCT DATA FROM A DATABASE. SELECT column_name, column_name
FROM	USED TO TELL WHICH TABLE DATA IS BEING RETRIEVED FROM. FROM table_name;
LIKE	USED IN A WHERE CLAUS TO SEARCH FOR A SPECIFIED PATTERN IN A COLUMN. SELECT column_name FROM table_name Where column_name LIKE pattern;
AND	DISPLAYS A RECORD IF BOTH CONFITIONS ARE TRUE. SELECT * FROM table_name WHERE column_name='condition_1' AND coulumn_name='condition_2'
OR	DISPLAYS A RECORD IF EITHER CONDITIONS ARE TRUE. SELECT * FROM table_name WHERE column_name='condition_1' OR coulumn_name='condition_2'
DELETE	USED TO DELETE ROWS IN A TABLE. DELETE FROM table_name WHERE column_name=some_value;
INSERT	USED TO INSERT NEW RECORDS IN A TABLE. INSERT INTO table_name VALUES (value1,value2,value3,...);
DROP	USED TO DELETE AN INDEX IN A TABLE. DROP INDEX index_name ON table_name
TRUNCATE	USED TO DELETE DATA INSIDE THE TABLE, BUT NOT THE TABLE ITSELF. TRUNCATE TABLE table_name
JOIN	USED TO SELECT ALL ROWS FROM BOTH TABLES AS LONG AS THERE IS A MATCH BETWEEN THE COLUMNS IN BOTH TABLES. SELECT column_name FROM table1 INNER JOIN table2 ON table1.column_name=table2.column_name;
WILDCARDS	USED TO SEARCH DATA WITHIN TABLE. % A substitute for zero or more characters. _ A substitute for a single character [charlist] Sets and ranges of characters to match

Resource summary

	Created by Sam Wright about 7 years ago