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DROP TABLE IF EXISTS t1; CREATE TABLE t1 ( key1 INT NOT NULL, key2 INT NOT NULL, key3 INT NOT NULL, key4 INT NOT NULL, key5 INT, key6 INT, key7 INT NOT NULL, key8 INT NOT NULL, INDEX i1(key1), INDEX i2(key2), INDEX i3(key3), INDEX i4(key4), INDEX i5(key5), INDEX i6(key6) ); ANALYZE TABLE t1; Table Op Msg_type Msg_text test.t1 analyze status OK DROP TABLE IF EXISTS t2; CREATE TABLE t2 LIKE t1; INSERT INTO t2 SELECT * FROM t1; ANALYZE TABLE t2; Table Op Msg_type Msg_text test.t2 analyze status Table is already up to date EXPLAIN UPDATE t1 SET key6=7 WHERE key1=80 OR key4=49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i4 i1,i4 4,4 NULL # Using union(i1,i4); Using where SELECT COUNT(*), SUM(key6) FROM t1 WHERE key1=80 OR key4=49; COUNT(*) SUM(key6) 3 129 UPDATE t1 SET key6=7 WHERE key1=80 OR key4=49; SELECT COUNT(*), SUM(key6) FROM t1 WHERE key1=80 OR key4=49; COUNT(*) SUM(key6) 3 21 EXPLAIN UPDATE t1 SET key1=18 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i2,i3,i5,i6 i3,i5,i2 4,5,4 NULL # Using union(intersect(i3,i5),i2); Using where SELECT COUNT(*), SUM(key1) FROM t1 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); COUNT(*) SUM(key1) 1 80 UPDATE t1 SET key1=18 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); SELECT COUNT(*), SUM(key1) FROM t1 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); COUNT(*) SUM(key1) 1 18 EXPLAIN UPDATE t1 SET key3=18 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2,i4,i5,i6 i4,i5 4,5 NULL # Using union(i4,i5); Using where SELECT COUNT(*), SUM(key3) FROM t1 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; COUNT(*) SUM(key3) 10 287 UPDATE t1 SET key3=18 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; SELECT COUNT(*), SUM(key3) FROM t1 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; COUNT(*) SUM(key3) 10 180 EXPLAIN UPDATE t1 SET key8=64 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i2,i3 i2,i3 4,4 NULL # Using union(i2,i3); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; COUNT(*) SUM(key8) 3 1185 UPDATE t1 SET key8=64 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; SELECT COUNT(*), SUM(key8) FROM t1 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; COUNT(*) SUM(key8) 3 192 EXPLAIN UPDATE t1 SET key8=18 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2,i3,i4,i5,i6 i5,i6 5,5 NULL # Using sort_union(i5,i6); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); COUNT(*) SUM(key8) 1 1 UPDATE t1 SET key8=18 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); SELECT COUNT(*), SUM(key8) FROM t1 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); COUNT(*) SUM(key8) 1 18 EXPLAIN UPDATE t1 SET key3=32 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2 i1,i2 4,4 NULL # Using sort_union(i1,i2); Using where SELECT COUNT(*), SUM(key3) FROM t1 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; COUNT(*) SUM(key3) 39 1168 UPDATE t1 SET key3=32 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; SELECT COUNT(*), SUM(key3) FROM t1 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; COUNT(*) SUM(key3) 39 1248 EXPLAIN UPDATE t1 SET key7=25 WHERE key1 IN (15,70) OR key2 IN (15,70); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2 i1,i2 4,4 NULL # Using sort_union(i1,i2); Using where SELECT COUNT(*), SUM(key7) FROM t1 WHERE key1 IN (15,70) OR key2 IN (15,70); COUNT(*) SUM(key7) 2 85 UPDATE t1 SET key7=25 WHERE key1 IN (15,70) OR key2 IN (15,70); SELECT COUNT(*), SUM(key7) FROM t1 WHERE key1 IN (15,70) OR key2 IN (15,70); COUNT(*) SUM(key7) 2 50 EXPLAIN UPDATE t1 SET key1=10 WHERE key5<5 OR key8<10 ORDER BY key1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # Using where; Using filesort SELECT COUNT(*), SUM(key1) FROM t1 WHERE key5<5 OR key8<10 ORDER BY key1; COUNT(*) SUM(key1) 11 56 UPDATE t1 SET key1=10 WHERE key5<5 OR key8<10 ORDER BY key1; SELECT COUNT(*), SUM(key1) FROM t1 WHERE key5<5 OR key8<10 ORDER BY key1; COUNT(*) SUM(key1) 11 110 EXPLAIN UPDATE t1 left join t2 ON (t2.key1=t2.key1) SET t1.key4=15 WHERE t1.key5=40 OR t1.key4=15; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i4,i5 i5,i4 5,4 NULL # Using union(i5,i4); Using where 1 SIMPLE t2 index NULL i1 4 NULL # Using where; Using index; Using join buffer (Block Nested Loop) SELECT COUNT(*), SUM(key4) FROM t1; COUNT(*) SUM(key4) 2057 2098421 UPDATE t1 left join t2 ON (t2.key1=t2.key1) SET t1.key4=15 WHERE t1.key5=40 OR t1.key4=15; SELECT COUNT(*), SUM(key4) FROM t1; COUNT(*) SUM(key4) 2057 2098396 EXPLAIN UPDATE t2 SET key7=7 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 index_merge i3,i4 i3,i4 4,4 NULL # Using union(i3,i4); Using where 2 SUBQUERY t1 index_merge i1,i5 i1,i5 4,5 NULL # Using union(i1,i5); Using where SELECT COUNT(*), SUM(key7) FROM t2 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); COUNT(*) SUM(key7) 0 NULL UPDATE t2 SET key7=7 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); SELECT COUNT(*), SUM(key7) FROM t2 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); COUNT(*) SUM(key7) 0 NULL EXPLAIN UPDATE t2 SET key2=2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 index_merge i1,i4 i1,i4 4,4 NULL # Using union(i1,i4); Using where 3 SUBQUERY t1 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where 2 SUBQUERY t1 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where SELECT COUNT(*), SUM(key2) FROM t2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); COUNT(*) SUM(key2) 1 25 UPDATE t2 SET key2=2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); SELECT COUNT(*), SUM(key2) FROM t2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); COUNT(*) SUM(key2) 1 2 EXPLAIN UPDATE t2 SET key3=20 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL # NULL 2 SUBQUERY t1 index_merge i4,i6 i6,i4 5,4 NULL # Using sort_union(i6,i4); Using where SELECT COUNT(*), SUM(key3) FROM t2 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); COUNT(*) SUM(key3) 2057 2098421 UPDATE t2 SET key3=20 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); SELECT COUNT(*), SUM(key3) FROM t2 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); COUNT(*) SUM(key3) 2057 41140 EXPLAIN UPDATE t1 SET key8=50 WHERE key5=80 OR key6=49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i5,i6 i5,i6 5,5 NULL # Using union(i5,i6); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE key5=80 OR key6=49; COUNT(*) SUM(key8) 1 64 UPDATE t1 SET key8=50 WHERE key5=80 OR key6=49; SELECT COUNT(*), SUM(key8) FROM t1 WHERE key5=80 OR key6=49; COUNT(*) SUM(key8) 1 50 DROP TABLE IF EXISTS t1; CREATE TABLE t1 ( key1 INT NOT NULL, key2 INT NOT NULL, key3 INT NOT NULL, key4 INT NOT NULL, key5 INT, key6 INT, key7 INT NOT NULL, key8 INT NOT NULL, INDEX i1(key1,key2), INDEX i2(key2,key1), INDEX i3(key3,key4), INDEX i4(key4,key3), INDEX i5(key5,key6), INDEX i6(key6,key5), INDEX i7(key7,key8), INDEX i8(key8,key7) ); ANALYZE TABLE t1; Table Op Msg_type Msg_text test.t1 analyze status OK DROP TABLE IF EXISTS t2; CREATE TABLE t2 LIKE t1; INSERT INTO t2 SELECT * FROM t1; ANALYZE TABLE t2; Table Op Msg_type Msg_text test.t2 analyze status Table is already up to date EXPLAIN UPDATE t1 SET key6=7 WHERE key1=80 OR key4=49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where SELECT COUNT(*), SUM(key6) FROM t1 WHERE key1=80 OR key4=49; COUNT(*) SUM(key6) 3 129 UPDATE t1 SET key6=7 WHERE key1=80 OR key4=49; SELECT COUNT(*), SUM(key6) FROM t1 WHERE key1=80 OR key4=49; COUNT(*) SUM(key6) 3 21 EXPLAIN UPDATE t1 SET key1=18 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i2,i3,i5,i6 i3,i2 4,4 NULL # Using sort_union(i3,i2); Using where; Using temporary SELECT COUNT(*), SUM(key1) FROM t1 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); COUNT(*) SUM(key1) 1 80 UPDATE t1 SET key1=18 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); SELECT COUNT(*), SUM(key1) FROM t1 WHERE (key3=80 AND key5 IS NULL) OR (key2=49 AND key6 IS NULL); COUNT(*) SUM(key1) 1 18 EXPLAIN UPDATE t1 SET key3=18 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2,i4,i5,i6 i4,i5 4,5 NULL # Using sort_union(i4,i5); Using where; Using temporary SELECT COUNT(*), SUM(key3) FROM t1 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; COUNT(*) SUM(key3) 10 287 UPDATE t1 SET key3=18 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; SELECT COUNT(*), SUM(key3) FROM t1 WHERE (key4=42 AND key6 IS NOT NULL) OR (key1>4 AND key5 IS NULL) AND key2<>50; COUNT(*) SUM(key3) 10 180 EXPLAIN UPDATE t1 SET key8=64 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i2,i3 i2,i3 4,4 NULL # Using sort_union(i2,i3); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; COUNT(*) SUM(key8) 3 1185 UPDATE t1 SET key8=64 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; SELECT COUNT(*), SUM(key8) FROM t1 WHERE key2=80 OR key3=1025 OR key4 <=> NULL; COUNT(*) SUM(key8) 3 192 EXPLAIN UPDATE t1 SET key8=18 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2,i3,i4,i5,i6 i5,i6 5,5 NULL # Using sort_union(i5,i6); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); COUNT(*) SUM(key8) 1 1 UPDATE t1 SET key8=18 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); SELECT COUNT(*), SUM(key8) FROM t1 WHERE (key1 < 3 OR key2 < 2) AND (key3 < 3 OR key4 < 3) AND (key5 < 2 OR key6 < 2); COUNT(*) SUM(key8) 1 18 EXPLAIN UPDATE t1 SET key3=32 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2 i1,i2 4,4 NULL # Using sort_union(i1,i2); Using where SELECT COUNT(*), SUM(key3) FROM t1 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; COUNT(*) SUM(key3) 39 1168 UPDATE t1 SET key3=32 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; SELECT COUNT(*), SUM(key3) FROM t1 WHERE key1 between 25 AND 40 OR key2 between 15 AND 49; COUNT(*) SUM(key3) 39 1248 EXPLAIN UPDATE t1 SET key7=25 WHERE key1 IN (15,70) OR key2 IN (15,70); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i1,i2 i1,i2 4,4 NULL # Using sort_union(i1,i2); Using where SELECT COUNT(*), SUM(key7) FROM t1 WHERE key1 IN (15,70) OR key2 IN (15,70); COUNT(*) SUM(key7) 2 85 UPDATE t1 SET key7=25 WHERE key1 IN (15,70) OR key2 IN (15,70); SELECT COUNT(*), SUM(key7) FROM t1 WHERE key1 IN (15,70) OR key2 IN (15,70); COUNT(*) SUM(key7) 2 50 EXPLAIN UPDATE t1 SET key1=10 WHERE key5<5 OR key8<10 ORDER BY key1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i5,i8 i5,i8 5,4 NULL # Using sort_union(i5,i8); Using where; Using filesort SELECT COUNT(*), SUM(key1) FROM t1 WHERE key5<5 OR key8<10 ORDER BY key1; COUNT(*) SUM(key1) 11 56 UPDATE t1 SET key1=10 WHERE key5<5 OR key8<10 ORDER BY key1; SELECT COUNT(*), SUM(key1) FROM t1 WHERE key5<5 OR key8<10 ORDER BY key1; COUNT(*) SUM(key1) 11 110 EXPLAIN UPDATE t1 left join t2 ON (t2.key1=t2.key1) SET t1.key4=15 WHERE t1.key5=40 OR t1.key4=15; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i4,i5 i5,i4 5,4 NULL # Using sort_union(i5,i4); Using where 1 SIMPLE t2 index NULL i1 8 NULL # Using where; Using index; Using join buffer (Block Nested Loop) SELECT COUNT(*), SUM(key4) FROM t1; COUNT(*) SUM(key4) 2057 2098421 UPDATE t1 left join t2 ON (t2.key1=t2.key1) SET t1.key4=15 WHERE t1.key5=40 OR t1.key4=15; SELECT COUNT(*), SUM(key4) FROM t1; COUNT(*) SUM(key4) 2057 2098396 EXPLAIN UPDATE t2 SET key7=7 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 index_merge i3,i4 i3,i4 4,4 NULL # Using sort_union(i3,i4); Using where 2 SUBQUERY t1 index_merge i1,i5 i1,i5 4,5 NULL # Using sort_union(i1,i5); Using where SELECT COUNT(*), SUM(key7) FROM t2 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); COUNT(*) SUM(key7) 0 NULL UPDATE t2 SET key7=7 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); SELECT COUNT(*), SUM(key7) FROM t2 WHERE (key3=28 OR key4=10) AND key6 < ANY (SELECT key6 FROM t1 WHERE key1=10 OR key5=3); COUNT(*) SUM(key7) 0 NULL EXPLAIN UPDATE t2 SET key2=2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where; Using temporary 3 SUBQUERY t1 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where 2 SUBQUERY t1 index_merge i1,i4 i1,i4 4,4 NULL # Using sort_union(i1,i4); Using where SELECT COUNT(*), SUM(key2) FROM t2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); COUNT(*) SUM(key2) 1 25 UPDATE t2 SET key2=2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); SELECT COUNT(*), SUM(key2) FROM t2 WHERE key1=25 OR key4=40 AND (key4 < SOME (SELECT key4 FROM t1 WHERE key1<5 OR key4<8) OR key1 < ANY (SELECT key1 FROM t1 WHERE key1<5 OR key4<7)); COUNT(*) SUM(key2) 1 2 EXPLAIN UPDATE t2 SET key3=20 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL # NULL 2 SUBQUERY t1 index_merge i4,i6 i6,i4 5,4 NULL # Using sort_union(i6,i4); Using where SELECT COUNT(*), SUM(key3) FROM t2 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); COUNT(*) SUM(key3) 2057 2098421 UPDATE t2 SET key3=20 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); SELECT COUNT(*), SUM(key3) FROM t2 WHERE EXISTS (SELECT * FROM t1 WHERE key6<3 OR key4<10); COUNT(*) SUM(key3) 2057 41140 EXPLAIN UPDATE t1 SET key8=50 WHERE key5=80 OR key6=49; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index_merge i5,i6 i5,i6 5,5 NULL # Using sort_union(i5,i6); Using where SELECT COUNT(*), SUM(key8) FROM t1 WHERE key5=80 OR key6=49; COUNT(*) SUM(key8) 1 64 UPDATE t1 SET key8=50 WHERE key5=80 OR key6=49; SELECT COUNT(*), SUM(key8) FROM t1 WHERE key5=80 OR key6=49; COUNT(*) SUM(key8) 1 50 DROP TABLE t1; DROP TABLE t2;