PHP MySQL加入

Question

Is there a way I could somehow do the following?

Table ONE

id   c_id   type
-------------------
1    1       7
2    2       7
3    3       5
4    4       7

Table TWO

id   title   live
-------------------
1    row1    1
2    row2    0
3    row3    0
4    row4    1

The c_id column links the data from table ONE to table TWO. Example: in table ONE, if the c_id is 2, that row in table ONE will be directly linked to table TWO's row with id 2, which has a title of "row2".

I want to select from table ONE, everything with type 7, but only if their associated data in table TWO has live set to 1.

Here's how I thought I'd do it, but this doesn't seem to work:

SELECT * FROM ONE, TWO WHERE ONE.type='7' AND TWO.live='1' ORDER BY ONE.id DESC LIMIT 5

I would expect the above to return only rows 1 and 4 from table ONE, because although table ONE has three rows with type "7", only rows 1 and 2's associated row in table TWO have live set to 1.

Answer 1

select * from one join two on c_id = two.id where type=7 and live = 1
order by one.id desc limit 5

Answer 2

您接近了...尝试使用隐式联接：

SELECT ONE.* FROM ONE, TWO WHERE ONE.type='7' AND TWO.live='1' AND ONE.c_id = TWO.id ORDER BY ONE.id DESC LIMIT 5