s******e
发帖数: 493 | 1 There is a table with gene_ids (‘gid’) and clone_ids (‘cid’). Each gene
only resides on a single clone and each clone may contain multiple genes. How
do you find how many genes are on each and every clone? Please provide the
SQL.
My ans:
select count(gene_ids.gid)
from gene_ids inner join clone_ids on gene_ids.cid = clone_ids.cid
group by (clone_ids.cid)
or
select(count(gene_ids.gid)
from gene_ids, clone_ids
where gene_ids.cid = clone_ids.cid
group by (clone_ids.cid)
Are they correct? |
n****f
发帖数: 905 | 2 How many table you have? 2 or 1 ?
Could you please show the structre and data?
What the data looks like then?
gene
How
【在 s******e 的大作中提到】
: There is a table with gene_ids (‘gid’) and clone_ids (‘cid’). Each gene
: only resides on a single clone and each clone may contain multiple genes. How
: do you find how many genes are on each and every clone? Please provide the
: SQL.
: My ans:
: select count(gene_ids.gid)
: from gene_ids inner join clone_ids on gene_ids.cid = clone_ids.cid
: group by (clone_ids.cid)
: or
: select(count(gene_ids.gid)
|
b**e
发帖数: 2 | 3 There is A table, right?
SELECT clone_ids, count(*) FROM tableName group by clone_ids
gene
How
【在 s******e 的大作中提到】
: There is a table with gene_ids (‘gid’) and clone_ids (‘cid’). Each gene
: only resides on a single clone and each clone may contain multiple genes. How
: do you find how many genes are on each and every clone? Please provide the
: SQL.
: My ans:
: select count(gene_ids.gid)
: from gene_ids inner join clone_ids on gene_ids.cid = clone_ids.cid
: group by (clone_ids.cid)
: or
: select(count(gene_ids.gid)
|
