1# "mtr --ps" returns different values in "Max length" 2--disable_ps_protocol 3--enable_metadata 4--vertical_results 5SELECT 6 a AS ___________a, 7 CASE WHEN a IS NOT NULL THEN a END AS case_______a, 8 CASE WHEN a IS NOT NULL THEN a ELSE a END AS case_____a_a, 9 COALESCE(a) AS coalesce___a, 10 COALESCE(a, a) AS coalesce_a_a, 11 IF(a IS NULL, a, a) AS if_______a_a, 12 IFNULL(a, a) AS ifnull___a_a, 13 LEAST(a, a) AS least____a_a, 14 GREATEST(a, a) AS greatest_a_a, 15 b AS ___________b, 16 CASE WHEN a IS NOT NULL THEN b END AS case_______b, 17 CASE WHEN a IS NOT NULL THEN b ELSE b END AS case_____b_b, 18 COALESCE(b) AS coalesce___b, 19 COALESCE(b, b) AS coalesce_b_b, 20 IF(a IS NULL, b, b) AS if_______b_b, 21 IFNULL(b, b) AS ifnull___b_b, 22 LEAST(b, b) AS least____b_b, 23 GREATEST(b, b) AS greatest_b_b 24FROM t1; 25SELECT 26 CASE WHEN a IS NOT NULL THEN a ELSE b END AS case_____a_b, 27 CASE WHEN a IS NOT NULL THEN b ELSE a END AS case_____b_a, 28 COALESCE(a, b) AS coalesce_a_b, 29 COALESCE(b, a) AS coalesce_b_a, 30 IF(a IS NULL, a, b) AS if_______a_b, 31 IF(a IS NULL, b, a) AS if_______b_a, 32 IFNULL(a, b) AS ifnull___a_b, 33 IFNULL(b, a) AS ifnull___b_a, 34 LEAST(a, b) AS least____a_b, 35 LEAST(b, a) AS least____b_a, 36 GREATEST(a, b) AS greatest_a_b, 37 GREATEST(b, a) AS greatest_b_a 38FROM t1; 39--horizontal_results 40--disable_metadata 41--enable_ps_protocol 42CREATE TABLE t2 AS 43SELECT 44 a AS ___________a, 45 CASE WHEN a IS NOT NULL THEN a END AS case_______a, 46 CASE WHEN a IS NOT NULL THEN a ELSE a END AS case_____a_a, 47 COALESCE(a) AS coalesce___a, 48 COALESCE(a, a) AS coalesce_a_a, 49 IF(a IS NULL, a, a) AS if_______a_a, 50 IFNULL(a, a) AS ifnull___a_a, 51 LEAST(a, a) AS least____a_a, 52 GREATEST(a, a) AS greatest_a_a, 53 b AS ___________b, 54 CASE WHEN a IS NOT NULL THEN b END AS case_______b, 55 CASE WHEN a IS NOT NULL THEN b ELSE b END AS case_____b_b, 56 COALESCE(b) AS coalesce___b, 57 COALESCE(b, b) AS coalesce_b_b, 58 IF(a IS NULL, b, b) AS if_______b_b, 59 IFNULL(b, b) AS ifnull___b_b, 60 LEAST(b, b) AS least____b_b, 61 GREATEST(b, b) AS greatest_b_b 62FROM t1; 63SHOW CREATE TABLE t2; 64DROP TABLE t2; 65SET STATEMENT sql_mode = 'NO_ENGINE_SUBSTITUTION' FOR 66CREATE TABLE t2 AS 67SELECT 68 CASE WHEN a IS NOT NULL THEN a ELSE b END AS case_____a_b, 69 CASE WHEN a IS NOT NULL THEN b ELSE a END AS case_____b_a, 70 COALESCE(a, b) AS coalesce_a_b, 71 COALESCE(b, a) AS coalesce_b_a, 72 IF(a IS NULL, a, b) AS if_______a_b, 73 IF(a IS NULL, b, a) AS if_______b_a, 74 IFNULL(a, b) AS ifnull___a_b, 75 IFNULL(b, a) AS ifnull___b_a, 76 LEAST(a, b) AS least____a_b, 77 LEAST(b, a) AS least____b_a, 78 GREATEST(a, b) AS greatest_a_b, 79 GREATEST(b, a) AS greatest_b_a 80FROM t1; 81SHOW CREATE TABLE t2; 82DROP TABLE t2; 83