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SET @@session.default_storage_engine = 'InnoDB';
SET @save_stats_persistent=@@GLOBAL.innodb_stats_persistent;
SET GLOBAL innodb_stats_persistent=0;
create table t1 (a int,
b int as (-a),
c int as (-a) persistent,
index (c));
insert into t1 (a) values (2), (1), (1), (3), (NULL);
create table t2 like t1;
insert into t2 (a) values (1);
create table t3 (a int primary key,
b int as (-a),
c int as (-a) persistent unique);
insert into t3 (a) values (2),(1),(3),(5),(4),(7);
# select_type=SIMPLE, type=system
select * from t2;
a b c
1 -1 -1
explain select * from t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1
select * from t2 where c=-1;
a b c
1 -1 -1
explain select * from t2 where c=-1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref c c 5 const 1
# select_type=SIMPLE, type=ALL
select * from t1 where b=-1;
a b c
1 -1 -1
1 -1 -1
explain select * from t1 where b=-1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using where
# select_type=SIMPLE, type=const
select * from t3 where a=1;
a b c
1 -1 -1
explain select * from t3 where a=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 const PRIMARY PRIMARY 4 const 1
# select_type=SIMPLE, type=range
select * from t3 where c>=-1;
a b c
1 -1 -1
explain select * from t3 where c>=-1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range c c 5 NULL 1 Using index condition
# select_type=SIMPLE, type=ref
select * from t1,t3 where t1.c=t3.c and t3.c=-1;
a b c a b c
1 -1 -1 1 -1 -1
1 -1 -1 1 -1 -1
explain select * from t1,t3 where t1.c=t3.c and t3.c=-1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 const c c 5 const 1
1 SIMPLE t1 ref c c 5 const 2
# select_type=PRIMARY, type=index,ALL
select * from t1 where b in (select c from t3);
a b c
2 -2 -2
1 -1 -1
1 -1 -1
3 -3 -3
explain select * from t1 where b in (select c from t3);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 5 Using where
1 PRIMARY t3 eq_ref c c 5 test.t1.b 1 Using index
# select_type=PRIMARY, type=range,ref
select * from t1 where c in (select c from t3 where c between -2 and -1);
a b c
2 -2 -2
1 -1 -1
1 -1 -1
explain select * from t1 where c in (select c from t3 where c between -2 and -1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t3 range c c 5 NULL 2 Using where; Using index
1 PRIMARY t1 ref c c 5 test.t3.c 1
# select_type=UNION, type=system
# select_type=UNION RESULT, type=<union1,2>
select * from t1 union select * from t2;
a b c
2 -2 -2
1 -1 -1
3 -3 -3
NULL NULL NULL
explain select * from t1 union select * from t2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 5
2 UNION t2 ALL NULL NULL NULL NULL 1
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
# select_type=DERIVED, type=system
set @tmp_optimizer_switch=@@optimizer_switch;
set optimizer_switch='derived_merge=off,derived_with_keys=off';
select * from (select a,b,c from t1) as t11;
a b c
2 -2 -2
1 -1 -1
1 -1 -1
3 -3 -3
NULL NULL NULL
explain select * from (select a,b,c from t1) as t11;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 5
2 DERIVED t1 ALL NULL NULL NULL NULL 5
set optimizer_switch=@tmp_optimizer_switch;
###
### Using aggregate functions with/without DISTINCT
###
# SELECT COUNT(*) FROM tbl_name
select count(*) from t1;
count(*)
5
explain select count(*) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL c 5 NULL 5 Using index
# SELECT COUNT(DISTINCT <non-vcol>) FROM tbl_name
select count(distinct a) from t1;
count(distinct a)
3
explain select count(distinct a) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5
# SELECT COUNT(DISTINCT <non-stored vcol>) FROM tbl_name
select count(distinct b) from t1;
count(distinct b)
3
explain select count(distinct b) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5
# SELECT COUNT(DISTINCT <stored vcol>) FROM tbl_name
select count(distinct c) from t1;
count(distinct c)
3
explain select count(distinct c) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL c 5 NULL 5 Using index for group-by
###
### filesort & range-based utils
###
# SELECT * FROM tbl_name WHERE <vcol expr>
select * from t3 where c >= -2;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where c >= -2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range c c 5 NULL 2 Using index condition
# SELECT * FROM tbl_name WHERE <non-vcol expr>
select * from t3 where a between 1 and 2;
a b c
1 -1 -1
2 -2 -2
explain select * from t3 where a between 1 and 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range PRIMARY PRIMARY 4 NULL 2 Using where
# SELECT * FROM tbl_name WHERE <non-indexed vcol expr>
select * from t3 where b between -2 and -1;
a b c
1 -1 -1
2 -2 -2
explain select * from t3 where b between -2 and -1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 ALL NULL NULL NULL NULL 6 Using where
# SELECT * FROM tbl_name WHERE <indexed vcol expr>
select * from t3 where c between -2 and -1;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where c between -2 and -1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range c c 5 NULL 2 Using index condition
# SELECT * FROM tbl_name WHERE <non-vcol expr> ORDER BY <non-indexed vcol>
select * from t3 where a between 1 and 2 order by b;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where a between 1 and 2 order by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range PRIMARY PRIMARY 4 NULL 2 Using where; Using filesort
# SELECT * FROM tbl_name WHERE <non-vcol expr> ORDER BY <indexed vcol>
select * from t3 where a between 1 and 2 order by c;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where a between 1 and 2 order by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range PRIMARY PRIMARY 4 NULL 2 Using where; Using filesort
# SELECT * FROM tbl_name WHERE <non-indexed vcol expr> ORDER BY <non-vcol>
select * from t3 where b between -2 and -1 order by a;
a b c
1 -1 -1
2 -2 -2
explain select * from t3 where b between -2 and -1 order by a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 index NULL PRIMARY 4 NULL 6 Using where
# SELECT * FROM tbl_name WHERE <non-indexed vcol expr> ORDER BY <non-indexed vcol>
select * from t3 where b between -2 and -1 order by b;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where b between -2 and -1 order by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 ALL NULL NULL NULL NULL 6 Using where; Using filesort
# SELECT * FROM tbl_name WHERE <indexed vcol expr> ORDER BY <non-indexed vcol>
select * from t3 where c between -2 and -1 order by b;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where c between -2 and -1 order by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range c c 5 NULL 2 Using index condition; Using filesort
# SELECT * FROM tbl_name WHERE <non-indexed vcol expr> ORDER BY <indexed vcol>
select * from t3 where b between -2 and -1 order by c;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where b between -2 and -1 order by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 ALL NULL NULL NULL NULL 6 Using where; Using filesort
# SELECT * FROM tbl_name WHERE <indexed vcol expr> ORDER BY <indexed vcol>
select * from t3 where c between -2 and -1 order by c;
a b c
2 -2 -2
1 -1 -1
explain select * from t3 where c between -2 and -1 order by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 range c c 5 NULL 2 Using index condition
# SELECT sum(<non-indexed vcol>) FROM tbl_name GROUP BY <non-indexed vcol>
select sum(b) from t1 group by b;
sum(b)
NULL
-3
-2
-2
explain select sum(b) from t1 group by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
# SELECT sum(<indexed vcol>) FROM tbl_name GROUP BY <indexed vcol>
select sum(c) from t1 group by c;
sum(c)
NULL
-3
-2
-2
explain select sum(c) from t1 group by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL c 5 NULL 5 Using index
# SELECT sum(<non-indexed vcol>) FROM tbl_name GROUP BY <indexed vcol>
select sum(b) from t1 group by c;
sum(b)
NULL
-3
-2
-2
explain select sum(b) from t1 group by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL c 5 NULL 5
# SELECT sum(<indexed vcol>) FROM tbl_name GROUP BY <non-indexed vcol>
select sum(c) from t1 group by b;
sum(c)
NULL
-3
-2
-2
explain select sum(c) from t1 group by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
SET GLOBAL innodb_stats_persistent=@save_stats_persistent;
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