EXCEPT Clause 

The EXCEPT clause returns only those rows that result from the first query without the second. The queries must match the number of columns, order, and type. The result of EXCEPT can contain duplicate rows.

Multiple EXCEPT statements are executed left to right if parenthesis are not specified. The EXCEPT operator has the same priority as the UNION clause and lower priority than the INTERSECT clause.

SELECT column1 [, column2 ]
FROM table1
[WHERE condition]

EXCEPT

SELECT column1 [, column2 ]
FROM table2
[WHERE condition]

The condition could be any expression based on your requirements.

Examples

Query:

SELECT number FROM numbers(1,10) EXCEPT SELECT number FROM numbers(3,6);

Result:

┌─number─┐
│      1 │
│      2 │
│      9 │
│     10 │
└────────┘

Query:

CREATE TABLE t1(one String, two String, three String) ENGINE=Memory();
CREATE TABLE t2(four String, five String, six String) ENGINE=Memory();

INSERT INTO t1 VALUES ('q', 'm', 'b'), ('s', 'd', 'f'), ('l', 'p', 'o'), ('s', 'd', 'f'), ('s', 'd', 'f'), ('k', 't', 'd'), ('l', 'p', 'o');
INSERT INTO t2 VALUES ('q', 'm', 'b'), ('b', 'd', 'k'), ('s', 'y', 't'), ('s', 'd', 'f'), ('m', 'f', 'o'), ('k', 'k', 'd');

SELECT * FROM t1 EXCEPT SELECT * FROM t2;

Result:

┌─one─┬─two─┬─three─┐
│ l   │ p   │ o     │
│ k   │ t   │ d     │
│ l   │ p   │ o     │
└─────┴─────┴───────┘

See Also

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