Difference between union and union all

UNION	UNION ALL
UNION removes duplicate rows.	“UNION ALL” does not remove the duplicate row. It returns all from all queries.
UNION uses a distinct sort	“UNION ALL” does not use a distinct sort, so the performance of “UNION ALL” is slightly higher than “UNION”.
UNION cannot work with a column that has a TEXT data type.	UNION ALL can work with all data type columns.

DECLARE @Table1 AS Table (ID INT, Name VARCHAR(10), PhoneNumber VARCHAR(12))  

DECLARE @Table2 AS Table (ID INT, Name VARCHAR(10), PhoneNumber VARCHAR(12))  

  

INSERT INTO @Table1 VALUES(1,'Tejas', '88996655')  

INSERT INTO @Table1 VALUES(2,'Jignesh', '99986655')  

INSERT INTO @Table2 VALUES(1,'Tejas', '88996655')  

INSERT INTO @Table2 VALUES(2,'Purvi', '99986655')  

SELECT * FROM @Table1  

UNION   

SELECT * FROM @Table2