/* Condition could be: * - constant, true * - constant, false * - constant, NULL * - non constant, non nullable * - non constant, nullable * * Then and else could be: * - constant, not NULL * - constant, NULL * - non constant, non nullable * - non constant, nullable * * Thus we have 5 * 4 * 4 = 80 combinations. */ DROP TABLE IF EXISTS nullable; CREATE VIEW nullable AS SELECT 1 AS constant_true, 0 AS constant_false, NULL AS constant_null, number % 3 = 1 AS cond_non_constant, number % 3 = 2 ? NULL : (number % 3 = 1) AS cond_non_constant_nullable, 'Hello' AS then_constant, 'World' AS else_constant, toString(number) AS then_non_constant, toString(-number) AS else_non_constant, nullIf(toString(number), '5') AS then_non_constant_nullable, nullIf(toString(-number), '-5') AS else_non_constant_nullable FROM system.numbers LIMIT 10; SELECT constant_true ? then_constant : else_constant AS res FROM nullable; SELECT constant_true ? then_constant : constant_null AS res FROM nullable; SELECT constant_true ? then_constant : else_non_constant AS res FROM nullable; SELECT constant_true ? then_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_true ? constant_null : else_constant AS res FROM nullable; SELECT constant_true ? constant_null : constant_null AS res FROM nullable; SELECT constant_true ? constant_null : else_non_constant AS res FROM nullable; SELECT constant_true ? constant_null : else_non_constant_nullable AS res FROM nullable; SELECT constant_true ? then_non_constant : else_constant AS res FROM nullable; SELECT constant_true ? then_non_constant : constant_null AS res FROM nullable; SELECT constant_true ? then_non_constant : else_non_constant AS res FROM nullable; SELECT constant_true ? then_non_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_true ? then_non_constant_nullable : else_constant AS res FROM nullable; SELECT constant_true ? then_non_constant_nullable : constant_null AS res FROM nullable; SELECT constant_true ? then_non_constant_nullable : else_non_constant AS res FROM nullable; SELECT constant_true ? then_non_constant_nullable : else_non_constant_nullable AS res FROM nullable; SELECT constant_false ? then_constant : else_constant AS res FROM nullable; SELECT constant_false ? then_constant : constant_null AS res FROM nullable; SELECT constant_false ? then_constant : else_non_constant AS res FROM nullable; SELECT constant_false ? then_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_false ? constant_null : else_constant AS res FROM nullable; SELECT constant_false ? constant_null : constant_null AS res FROM nullable; SELECT constant_false ? constant_null : else_non_constant AS res FROM nullable; SELECT constant_false ? constant_null : else_non_constant_nullable AS res FROM nullable; SELECT constant_false ? then_non_constant : else_constant AS res FROM nullable; SELECT constant_false ? then_non_constant : constant_null AS res FROM nullable; SELECT constant_false ? then_non_constant : else_non_constant AS res FROM nullable; SELECT constant_false ? then_non_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_false ? then_non_constant_nullable : else_constant AS res FROM nullable; SELECT constant_false ? then_non_constant_nullable : constant_null AS res FROM nullable; SELECT constant_false ? then_non_constant_nullable : else_non_constant AS res FROM nullable; SELECT constant_false ? then_non_constant_nullable : else_non_constant_nullable AS res FROM nullable; SELECT constant_null ? then_constant : else_constant AS res FROM nullable; SELECT constant_null ? then_constant : constant_null AS res FROM nullable; SELECT constant_null ? then_constant : else_non_constant AS res FROM nullable; SELECT constant_null ? then_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_null ? constant_null : else_constant AS res FROM nullable; SELECT constant_null ? constant_null : constant_null AS res FROM nullable; SELECT constant_null ? constant_null : else_non_constant AS res FROM nullable; SELECT constant_null ? constant_null : else_non_constant_nullable AS res FROM nullable; SELECT constant_null ? then_non_constant : else_constant AS res FROM nullable; SELECT constant_null ? then_non_constant : constant_null AS res FROM nullable; SELECT constant_null ? then_non_constant : else_non_constant AS res FROM nullable; SELECT constant_null ? then_non_constant : else_non_constant_nullable AS res FROM nullable; SELECT constant_null ? then_non_constant_nullable : else_constant AS res FROM nullable; SELECT constant_null ? then_non_constant_nullable : constant_null AS res FROM nullable; SELECT constant_null ? then_non_constant_nullable : else_non_constant AS res FROM nullable; SELECT constant_null ? then_non_constant_nullable : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant ? then_constant : else_constant AS res FROM nullable; SELECT cond_non_constant ? then_constant : constant_null AS res FROM nullable; SELECT cond_non_constant ? then_constant : else_non_constant AS res FROM nullable; SELECT cond_non_constant ? then_constant : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant ? constant_null : else_constant AS res FROM nullable; SELECT cond_non_constant ? constant_null : constant_null AS res FROM nullable; SELECT cond_non_constant ? constant_null : else_non_constant AS res FROM nullable; SELECT cond_non_constant ? constant_null : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant ? then_non_constant : else_constant AS res FROM nullable; SELECT cond_non_constant ? then_non_constant : constant_null AS res FROM nullable; SELECT cond_non_constant ? then_non_constant : else_non_constant AS res FROM nullable; SELECT cond_non_constant ? then_non_constant : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant ? then_non_constant_nullable : else_constant AS res FROM nullable; SELECT cond_non_constant ? then_non_constant_nullable : constant_null AS res FROM nullable; SELECT cond_non_constant ? then_non_constant_nullable : else_non_constant AS res FROM nullable; SELECT cond_non_constant ? then_non_constant_nullable : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant_nullable ? then_constant : else_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_constant : constant_null AS res FROM nullable; SELECT cond_non_constant_nullable ? then_constant : else_non_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_constant : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant_nullable ? constant_null : else_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? constant_null : constant_null AS res FROM nullable; SELECT cond_non_constant_nullable ? constant_null : else_non_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? constant_null : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant : else_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant : constant_null AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant : else_non_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant : else_non_constant_nullable AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant_nullable : else_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant_nullable : constant_null AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant_nullable : else_non_constant AS res FROM nullable; SELECT cond_non_constant_nullable ? then_non_constant_nullable : else_non_constant_nullable AS res FROM nullable; DROP TABLE nullable;