drop table if exists t1,t2;
create table t1 (a int);
select count(a) as b from t1 where a=0 having b > 0;
b
insert into t1 values (null);
select count(a) as b from t1 where a=0 having b > 0;
b
select count(a) as b from t1 where a=0 having b >=0;
b
0
explain extended select count(a) as b from t1 where a=0 having b >=0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
Warnings:
Note	1003	select high_priority count(test.t1.a) AS `b` from test.t1 where (test.t1.a = 0) having (count(test.t1.a) >= 0)
drop table t1;
CREATE TABLE t1 (
raw_id int(10) NOT NULL default '0',
chr_start int(10) NOT NULL default '0',
chr_end int(10) NOT NULL default '0',
raw_start int(10) NOT NULL default '0',
raw_end int(10) NOT NULL default '0',
raw_ori int(2) NOT NULL default '0'
);
INSERT INTO t1 VALUES (469713,1,164123,1,164123,1),(317330,164124,317193,101,153170,1),(469434,317194,375620,101,58527,1),(591816,375621,484273,1,108653,1),(591807,484274,534671,91,50488,1),(318885,534672,649362,101,114791,1),(318728,649363,775520,102,126259,1),(336829,775521,813997,101,38577,1),(317740,813998,953227,101,139330,1),(1,813998,953227,101,139330,1);
CREATE TABLE t2 (
id int(10) unsigned NOT NULL default '0',
contig_id int(10) unsigned NOT NULL default '0',
seq_start int(10) NOT NULL default '0',
seq_end int(10) NOT NULL default '0',
strand tinyint(2) NOT NULL default '0',
KEY id (id)
);
INSERT INTO t2 VALUES (133195,469713,61327,61384,1),(133196,469713,64113,64387,1),(133197,1,1,1,0),(133197,1,1,1,-2);
SELECT e.id,
MIN( IF(sgp.raw_ori=1,
(e.seq_start+sgp.chr_start-sgp.raw_start),  
(sgp.chr_start+sgp.raw_end-e.seq_end))) as start, 
MAX( IF(sgp.raw_ori=1,
(e.seq_end+sgp.chr_start-sgp.raw_start),  
(sgp.chr_start+sgp.raw_end-e.seq_start))) as end, 
AVG(IF (sgp.raw_ori=1,e.strand,(-e.strand))) as chr_strand 
FROM  t1 sgp,
t2 e  
WHERE sgp.raw_id=e.contig_id 
GROUP BY e.id 
HAVING chr_strand= -1 and end >= 0 
AND start <= 999660;
id	start	end	chr_strand
133197	813898	813898	-1.0000
drop table t1,t2;
CREATE TABLE t1 (Fld1 int(11) default NULL,Fld2 int(11) default NULL);
INSERT INTO t1 VALUES (1,10),(1,20),(2,NULL),(2,NULL),(3,50);
select Fld1, max(Fld2) as q from t1 group by Fld1 having q is not null;
Fld1	q
1	20
3	50
select Fld1, max(Fld2) from t1 group by Fld1 having max(Fld2) is not null;
Fld1	max(Fld2)
1	20
3	50
select Fld1, max(Fld2) from t1 group by Fld1 having avg(Fld2) is not null;
Fld1	max(Fld2)
1	20
3	50
select Fld1, max(Fld2) from t1 group by Fld1 having std(Fld2) is not null;
Fld1	max(Fld2)
1	20
3	50
select Fld1, max(Fld2) from t1 group by Fld1 having variance(Fld2) is not null;
Fld1	max(Fld2)
1	20
3	50
drop table t1;
create table t1 (id int not null, qty int not null);
insert into t1 values (1,2),(1,3),(2,4),(2,5);
select id, sum(qty) as sqty from t1 group by id having sqty>2;
id	sqty
1	5
2	9
select sum(qty) as sqty from t1 group by id having count(id) > 0;
sqty
5
9
select sum(qty) as sqty from t1 group by id having count(distinct id) > 0;
sqty
5
9
drop table t1;
