SELECT a
FROM t1
CROSS JOIN t2
SELECT a
FROM t1
ALL INNER JOIN t2 ON a = t2.a
WHERE a = t2.a
SELECT a
FROM t1
ALL INNER JOIN t2 ON b = t2.b
WHERE b = t2.b
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        a AS `--t1.a`,
        t2.a AS `--t2.a`
    FROM t1
    ALL INNER JOIN t2 ON `--t1.a` = `--t2.a`
) AS `--.s`
ALL INNER JOIN t3 ON `--t1.a` = a
WHERE (`--t1.a` = `--t2.a`) AND (`--t1.a` = a)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        b AS `--t1.b`,
        a AS `--t1.a`,
        t2.b AS `--t2.b`
    FROM t1
    ALL INNER JOIN t2 ON `--t1.b` = `--t2.b`
) AS `--.s`
ALL INNER JOIN t3 ON `--t1.b` = b
WHERE (`--t1.b` = `--t2.b`) AND (`--t1.b` = b)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.a`,
        `--t2.a`,
        a AS `--t3.a`
    FROM 
    (
        SELECT
            a AS `--t1.a`,
            t2.a AS `--t2.a`
        FROM t1
        ALL INNER JOIN t2 ON `--t1.a` = `--t2.a`
    ) AS `--.s`
    ALL INNER JOIN t3 ON `--t1.a` = `--t3.a`
) AS `--.s`
ALL INNER JOIN t4 ON `--t1.a` = a
WHERE (`--t1.a` = `--t2.a`) AND (`--t1.a` = `--t3.a`) AND (`--t1.a` = a)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.b`,
        `--t1.a`,
        `--t2.b`,
        b AS `--t3.b`
    FROM 
    (
        SELECT
            b AS `--t1.b`,
            a AS `--t1.a`,
            t2.b AS `--t2.b`
        FROM t1
        ALL INNER JOIN t2 ON `--t1.b` = `--t2.b`
    ) AS `--.s`
    ALL INNER JOIN t3 ON `--t1.b` = `--t3.b`
) AS `--.s`
ALL INNER JOIN t4 ON `--t1.b` = b
WHERE (`--t1.b` = `--t2.b`) AND (`--t1.b` = `--t3.b`) AND (`--t1.b` = b)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.a`,
        `--t2.a`,
        a AS `--t3.a`
    FROM 
    (
        SELECT
            a AS `--t1.a`,
            t2.a AS `--t2.a`
        FROM t1
        ALL INNER JOIN t2 ON `--t2.a` = `--t1.a`
    ) AS `--.s`
    ALL INNER JOIN t3 ON `--t2.a` = `--t3.a`
) AS `--.s`
ALL INNER JOIN t4 ON `--t2.a` = a
WHERE (`--t2.a` = `--t1.a`) AND (`--t2.a` = `--t3.a`) AND (`--t2.a` = a)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.a`,
        `--t2.a`,
        a AS `--t3.a`
    FROM 
    (
        SELECT
            a AS `--t1.a`,
            t2.a AS `--t2.a`
        FROM t1
        CROSS JOIN t2
    ) AS `--.s`
    ALL INNER JOIN t3 ON (`--t3.a` = `--t1.a`) AND (`--t3.a` = `--t2.a`)
) AS `--.s`
ALL INNER JOIN t4 ON `--t3.a` = a
WHERE (`--t3.a` = `--t1.a`) AND (`--t3.a` = `--t2.a`) AND (`--t3.a` = a)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.a`,
        `--t2.a`,
        a AS `--t3.a`
    FROM 
    (
        SELECT
            a AS `--t1.a`,
            t2.a AS `--t2.a`
        FROM t1
        CROSS JOIN t2
    ) AS `--.s`
    CROSS JOIN t3
) AS `--.s`
ALL INNER JOIN t4 ON (a = `--t1.a`) AND (a = `--t2.a`) AND (a = `--t3.a`)
WHERE (a = `--t1.a`) AND (a = `--t2.a`) AND (a = `--t3.a`)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        `--t1.a`,
        `--t2.a`,
        a AS `--t3.a`
    FROM 
    (
        SELECT
            a AS `--t1.a`,
            t2.a AS `--t2.a`
        FROM t1
        ALL INNER JOIN t2 ON `--t1.a` = `--t2.a`
    ) AS `--.s`
    ALL INNER JOIN t3 ON `--t2.a` = `--t3.a`
) AS `--.s`
ALL INNER JOIN t4 ON `--t3.a` = a
WHERE (`--t1.a` = `--t2.a`) AND (`--t2.a` = `--t3.a`) AND (`--t3.a` = a)
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT `--t1.a`
    FROM 
    (
        SELECT a AS `--t1.a`
        FROM t1
        CROSS JOIN t2
    ) AS `--.s`
    CROSS JOIN t3
) AS `--.s`
CROSS JOIN t4
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT `--t1.a`
    FROM 
    (
        SELECT a AS `--t1.a`
        FROM t1
        CROSS JOIN t2
    ) AS `--.s`
    CROSS JOIN t3
) AS `--.s`
CROSS JOIN t4
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT a AS `--t1.a`
    FROM t1
    CROSS JOIN t2
) AS `--.s`
CROSS JOIN t3
SELECT `--t1.a` AS `t1.a`
FROM 
(
    SELECT
        a AS `--t1.a`,
        t2.a AS `--t2.a`
    FROM t1
    ALL INNER JOIN t2 ON `--t1.a` = `--t2.a`
) AS `--.s`
CROSS JOIN t3
SELECT * FROM t1, t2
1	1	1	1
1	1	1	\N
2	2	1	1
2	2	1	\N
3	3	1	1
3	3	1	\N
4	4	1	1
4	4	1	\N
SELECT * FROM t1, t2 WHERE t1.a = t2.a
1	1	1	1
1	1	1	\N
SELECT t1.a, t2.a FROM t1, t2 WHERE t1.b = t2.b
1	1
SELECT t1.a, t2.b, t3.b FROM t1, t2, t3 WHERE t1.a = t2.a AND t1.a = t3.a
1	1	1
1	1	\N
1	\N	1
1	\N	\N
SELECT t1.a, t2.b, t3.b FROM t1, t2, t3 WHERE t1.b = t2.b AND t1.b = t3.b
1	1	1
SELECT t1.a, t2.b, t3.b, t4.b FROM t1, t2, t3, t4 WHERE t1.a = t2.a AND t1.a = t3.a AND t1.a = t4.a
1	1	1	1
1	1	1	\N
1	1	\N	1
1	1	\N	\N
1	\N	1	1
1	\N	1	\N
1	\N	\N	1
1	\N	\N	\N
SELECT t1.a, t2.b, t3.b, t4.b FROM t1, t2, t3, t4 WHERE t1.b = t2.b AND t1.b = t3.b AND t1.b = t4.b
1	1	1	1
SELECT t1.a, t2.b, t3.b, t4.b FROM t1, t2, t3, t4 WHERE t1.a = t2.a AND t2.a = t3.a AND t3.a = t4.a
1	1	1	1
1	1	1	\N
1	1	\N	1
1	1	\N	\N
1	\N	1	1
1	\N	1	\N
1	\N	\N	1
1	\N	\N	\N