SQL Basic Statement(INSERT/DELETE/UPDATE/SELECT)

1. SELECT Basic Statement

-- SQL SELECT SyntaxSELECT  column_name, column_name, *FROM table_name;

If we want to only get the distinct value, we could use DISTINCT keywords

--DISTINCTSELECT DISTINCT column_nameFROM table_name;

 WHERE Clause is used to filter records.

 

--SQL WHERE SyntaxSELECT col1, col2,FROM tableWHERE col_name operator value;

Operators in the WHERE ClauseOperatorDescription= Equal<>Not Equal>Greater than< Less than>=Greater than/equal<=Less than /equalBETWEEN A rangeLIKESearch for a patternINto specify multiple possible values for a column

AND & OR in WHERE Clause

AND: for both first condition AND second condition on Where is true

OR: for either first condition OR second condition in Where is true;

SQL ORDER BY keyword

-- SQL ORDER BY SyntaxSELECT colname, colname2FROM tablenameWHERE conditionORDER BY colname ASC|DESC

2. SQL INSERT INTO Statement

--SQL INSERT INTO syntaxINSERT INTO tablenameVALUES(value1, value2, value3,....);

--Specify tablename, colname and valueINSERT INTO tablename(col1, col2, col3,...)VALUES(val1, val2, val3,...)

3. SQL UPDATE statement

--SQL UPDATE SyntaxUPDATE tablenameSET col1 = value1, col2 = val2, ...WHERE someCol = someVal

Note: Be careful with the Where condition.

4. SEL DELETE Statement

Delete records in a table

--DELETE SyntaxDELETE FROM tableNameWHERE somecol = someval