ClickHouse/docs/en/sql-reference/statements/select/intersect.md

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INTERSECT

INTERSECT Clause

The INTERSECT clause returns only those rows that result from both the first and the second queries. The queries must match the number of columns, order, and type. The result of INTERSECT can contain duplicate rows.

Multiple INTERSECT statements are executes left to right if parenthesis are not specified. The INTERSECT operator has a higher priority than the UNION and EXCEPT clause.

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

INTERSECT

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) INTERSECT SELECT number FROM numbers(3,6);

Result:

┌─number─┐
│      3 │
│      4 │
│      5 │
│      6 │
│      7 │
│      8 │
└────────┘

Query:

SELECT number FROM numbers(1,10) WHERE number > 5 INTERSECT SELECT number FROM numbers(3,6) WHERE number < 7;

Result:

┌─number─┐
│      6 │
└────────┘

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 INTERSECT SELECT * FROM t2;

Result:

┌─one─┬─two─┬─three─┐
│ q   │ m   │ b     │
│ s   │ d   │ f     │
│ s   │ d   │ f     │
│ s   │ d   │ f     │
└─────┴─────┴───────┘

See Also

• UNION
• EXCEPT