JOIN syntax and order for multiple tables - sql

Question

SQL Gurus,
I have a query that uses the "old" style of join syntax as follows using 7 tables (table and column names changed to protect the innocent), as shown below:
SELECT v1_col, p1_col
FROM p1_tbl, p_tbl, p2_tbl, p3_tbl, v1_tbl, v2_tbl, v3_tbl
WHERE p1_code = 1
AND v1_code = 1
AND p1_date >= v1_date
AND p_uid = p1_uid
AND p2_uid = p1_uid AND p2_id = v2_id
AND p3_uid = p1_uid AND p3_id = v3_id
AND v2_uid = v1_uid
AND v3_uid = v1_uid
The query works just fine and produces the results it is supposed to, but as an academic exercise, I tried to rewrite the query using the more standard JOIN syntax, for example, below is one version I tried:
SELECT V1.v1_col, P1.p1_col
FROM p1_tbl P1, v1_tbl V1
JOIN p_tbl P ON ( P.p_uid = P1.p1_uid )
JOIN p2_tbl P2 ON ( P2.p2_uid = P1.p1_uid AND P2.p2_id = V2.v2_id )
JOIN p3_tbl P3 ON ( P3.p3_uid = P1.p1_uid AND P3.p3_id = V3.v3_id )
JOIN v2_tbl V2 ON ( V2.v2_uid = V1.v1_uid )
JOIN v3_tbl V3 ON ( V3.v3_uid = V1.v1_uid )
WHERE P1.p1_code = 1
AND V1.v1_code = 1
AND P1.p1_date >= V1.v1_date
But, no matter how I arrange the JOINs (using MS SQL 2008 R2), I keep running into the error:
The Multi-part identifier "col-name" could not be bound,
where "col-name" varies depending on the order of the JOINs I am attempting...
Does anyone have any good examples on how use the JOIN syntax with this number of tables??
Thanks in advance!

Answer 1

When you use JOIN-syntax you can only access columns from tables in your current join or previous joins. In fact it's easier to write the old syntax, but it's more error-prone, e.g. you can easily forget a join-condition.
This should be what you want.
SELECT v1_col, p1_col
FROM p1_tbl
JOIN v1_tbl ON p1_date >= v1_date
JOIN v2_tbl ON v2_uid = v1_uid
JOIN v3_tbl ON v3_uid = v1_uid
JOIN p_tbl ON p_uid = p1_uid
JOIN p2_tbl ON p2_uid = p1_uid AND p2_id = v2_id
JOIN p3_tbl ON p3_uid = p1_uid AND p3_id = v3_id
WHERE p1_code = 1
AND v1_code = 1

Answer 2

You are not naming the tables in your join such that it doesn't know which column is from which table. Try something like:
SELECT a.v1_col, b.p1_col
FROM p1_tbl b
JOIN p_tbl a ON b.p_uid = a.p1_uid
WHERE b.p1_code = 1

Answer 3

From your query above, I am assuming a naming convention of p2_uid comes from p2_tbl. Below id my best interpretation of WHERE joins to using INNER joins.
SELECT
v1_col, p1_col
FROM
p1_tbl
INNER JOIN p1_tbl
ON p1_tbl.p1_date >= v1_tbl.v1_date
INNER JOIN p_tbl
ON p_tbl.p_uid = p1_tbl.p1_uid
INNER JOIN p2_tbl
ON p2_tbl.p2_uid = p1_tbl.p1_uid
INNER JOIN v2_tbl
ON p2_tbl.p2_id = v2_tbl.v2_id
INNER JOIN p3_tbl
ON p3_tbl.p3_uid = p1_tbl.p1_uid
INNER JOIN v3_tbl
ON p3_tbl.p3_id = v3_tbl.v3_id
INNER JOIN v1_tbl
ON v1_tbl.v1_uid = v2_tbl.v2_uid
AND v1_tbl.v1_uid = v3_tbl.v2_uid
WHERE
p1_code = 1
AND
v1_code = 1
Some general points I have found useful in SQL statements with many joins.
Always fully qualify the names. I.e dont use ID , rahter use
TableName.ID
Dont use aliases unless there is meaning. (I.e. joining a table to
its self where aliasing is needed.)