How to do this thing?
I have two table
Table1:
-id
-table2_id_1
-table2_id_2
Table2:
-id
-table3_id
Table3:
-id
-table4_id
-table5_id
-table6_id
Table4, Table5 and Table6:
-id
-name
-date
Main table is Table1
db(db.Table1).select()
I need to join twice Table2(colums) in witch i need to join Table3(in each table2_id_1 and table2_id_2 field table3_id is equals), than join Table4,Table5,Table6
I don't know, if I really got, what you are trying to do, but if you just want to join the tables according to the id's, something like that should work:
SELECT *
FROM table1 a JOIN table2 b ON (a.table2_id_1 = b.id) JOIN
table2 c ON (a.table2_id_2 = c.id) JOIN
table3 d ON (b.table3_id = d.id) JOIN
table3 e ON (c.table3_id = e.id) JOIN
table4 f ON (d.table4_id = f.id) JOIN
table5 g ON (d.table5_id = g.id) JOIN
table6 h ON (d.table6_id = h.id) JOIN
table4 i ON (e.table4_id = i.id) JOIN
table5 j ON (e.table5_id = j.id) JOIN
table6 k ON (e.table6_id = k.id)
Related
I have encountered a situations that it takes a long time when I tried to merge multiple tables together. I am aware of two SQL line that will work but I don't know which one is better or whether there is any difference between them.
SQL1:
SELECT a.code,a.date,b.varaible1,c.varaible2 \
FROM TABLEA a,TABLEB b,TABLEC c\
WHERE a.date = b.date\
AND a.code = b.code\
AND a.date = c.date
SQL2:
SELECT a.code,a.date,b.varaible1,c.varaible2 \
FROM TABLEA a\
JOIN TABLEB b\
on a.date = b.date\
AND a.code = b.code \
JOIN TABLEC c\
on a.date = c.date
so is there any difference between the two? or it depends?
I have this code:
query = """SELECT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_ FROM set_payment7777 sp JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT WHERE sp.date_ = (SELECT MAX(date_) FROM set_payment7777 GROUP BY customer_VAT) GROUP BY sp.customer_VAT"""
mycursor.execute(query)
for row in mycursor:
#do something
but I get the error:
mysql.connector.errors.DataError: 1242 (21000): Subquery returns more
than 1 row
You have several customer_VAT then your subquery return more than a row .. for avoid this you could use a join on the subquery
query = """SELECT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_
FROM set_payment7777 sp
INNER JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT
INNER JOIN (
SELECT MAX(date_) FROM set_payment7777
GROUP BY customer_VAT
) t on t.customer_VAT = sp.customer_VAT
GROUP BY sp.customer_VAT"""
anyway you have a main select without aggregation function then you should avoid an improper use of group by. In this case use DISTINCT if you need not repeated result
query = """SELECT DISTINCT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_
FROM set_payment7777 sp
INNER JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT
INNER JOIN (
SELECT MAX(date_) FROM set_payment7777
GROUP BY customer_VAT
) t on t.customer_VAT = sp.customer_VAT"""
I have some problems with a SQL for Python that I hope you can help me with - I'm trying to retrieve some data from wordpress/woocommerce.
My code:
cursor.execute("
SELECT t1.ID, t1.post_date, t2.meta_value AS first_name, t3.meta_value AS last_name
FROM test_posts t1
LEFT JOIN test_postmeta t2
ON t1.ID = t2.post_id
WHERE t2.meta_key = '_billing_first_name' and t2.post_id = t1.ID
LEFT JOIN test_postmeta t3
ON t1.ID = t3.post_id
WHERE t3.meta_key = '_billing_last_name' and t3.post_id = t1.ID
GROUP BY t1.ID
ORDER BY t1.post_date DESC LIMIT 20")
I'm getting the following error:
mysql.connector.errors.ProgrammingError: 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LEFT JOIN test_postmeta t3 ON t1.ID = t3.post_id WHERE t3.meta_key = '_billing' at line 1
What am I doing wrong?
Thanks in advance.
There should be only 1 WHERE clause before GROUP BY.
But since you use LEFT joins, setting a condition on the right table like t2.meta_key = '_billing_first_name' you get an INNER join instead because you reject unmatched rows.
So set all the conditions in the ON clauses:
cursor.execute("
SELECT t1.ID, t1.post_date, t2.meta_value AS first_name, t3.meta_value AS last_name
FROM test_posts t1
LEFT JOIN test_postmeta t2
ON t1.ID = t2.post_id AND t2.meta_key = '_billing_first_name'
LEFT JOIN test_postmeta t3
ON t1.ID = t3.post_id AND t3.meta_key = '_billing_last_name'
GROUP BY t1.ID
ORDER BY t1.post_date DESC LIMIT 20")
Although this query may be syntactically correct for MySql, it does not make sense to use GROUP BY since you do not do any aggregation.
Your SQL syntax is incorrect. Try this:
cursor.execute("
SELECT t1.ID, t1.post_date, t2.meta_value AS first_name, t3.meta_value AS last_name
FROM test_posts t1
LEFT JOIN test_postmeta t2 ON t1.ID = t2.post_id
LEFT JOIN test_postmeta t3 ON t1.ID = t3.post_id
WHERE t3.meta_key = '_billing_last_name' and t2.meta_key = '_billing_first_name'
GROUP BY t1.ID
ORDER BY t1.post_date DESC LIMIT 20")
It might be worth reading a little bit about SQL Joins and WHERE statements.
Snowflake DB does not support recursive with clause function , Need help me on how to achieve below query . Below query works well in Teradata
If any one also can help me to achieve using Python that would be great
WITH RECURSIVE RECURTEMP(ID,KCODE,LVL)
AS(SELECT ID, MIN(KCODE) AS KCODE,1
FROM TABLE_A
GROUP BY 1
UNION ALL
SELECT b.ID, trim(a.KCODE)|| ';'||trim(b.KCODE), LVL+1
FROM TABLE_A a
INNER JOIN RECURTEMP b ON a.ID = b.ID AND a.KCODE > b.KCODE
)
SELECT * FROM RECURTEMP
![Result]: https://imgur.com/a/ppSRXeT
CREATE TABLE MYTABLE (
ID VARCHAR2(50),
KCODE VARCHAR2(50)
);
INSERT INTO MYTABLE VALUES ('ABCD','K10');
INSERT INTO MYTABLE VALUES ('ABCD','K53');
INSERT INTO MYTABLE VALUES ('ABCD','K55');
INSERT INTO MYTABLE VALUES ('ABCD','K56');
COMMIT;
OUTPUT as below
ID KCODE LEVEL
--------------------------------------
ABCD K10 1
ABCD K53;K10 2
ABCD K55;K10 2
ABCD K56;K10 2
ABCD K55;K53;K10 3
ABCD K56;K53;K10 3
ABCD K56;K55;K10 3
ABCD K56;K55;K53;K10 4
Recursive WITH is now supported in Snowflake.
Your query
WITH RECURSIVE RECURTEMP(ID,KCODE,LVL) AS(
SELECT
ID,
MIN(KCODE) AS KCODE,
1
FROM
TABLE_A
GROUP BY
1
UNION ALL
SELECT
b.ID,
trim(a.KCODE) || ';' || trim(b.KCODE) AS KCODE,
LVL+1
FROM
TABLE_A a
INNER JOIN RECURTEMP b ON (a.ID = b.ID AND a.KCODE > b.KCODE)
)
SELECT * FROM RECURTEMP
Link to article is below.
https://docs.snowflake.net/manuals/user-guide/queries-cte.html#overview-of-recursive-cte-syntax
I have constructed a sql clause where I reference the same table as a and b to compare the two geometries as a postgis command.
I would like to pass a value into the sql statement using the %s operator and read the result into a pandas dataframe using to_sql, params kwargs. Currently my code will allow for one value to be passed to one %s but i'm looking for multiple insertions of the same list of values.
I'm connecting to a postgresql database using psycopg2.
Simplified code is below
sql = """
SELECT
st_distance(a.the_geom, b.the_geom, true) AS dist
FROM
(SELECT
table.*
FROM table
WHERE id in %s) AS a,
(SELECT
table.*
FROM table
WHERE id in %s) AS b
WHERE a.nid <> b.nid """
sampList = (14070,11184)
df = pd.read_sql(sql, con=conn, params = [sampList])
Basically i'm looking to replace both %s with the sampList value in both places. The code as written will only replace the first value indicating ': list index out of range. If I adjust to having one %s and replacing the second in statement with numbers the code runs, but ultimately I would like away to repeat those values.
You dont need the subqueries, just join the table with itself:
SELECT a.*, b.* -- or whatwever
, st_distance(a.the_geom, b.the_geom, true) AS dist
FROM ztable a
JOIN ztable b ON a.nid < b.nid
WHERE a.id IN (%s)
AND b.id IN (%s)
;
avoid repetition by using a CTE (this may be non-optimal, performance-wise)
WITH zt AS (
SELECT * FROM ztable
WHERE id IN (%s)
)
SELECT a.*, b.* -- or whatever
, st_distance(a.the_geom, b.the_geom, true) AS dist
FROM zt a
JOIN zt b ON a.nid < b.nid
;
Performance-wise, I would just stick to the first version, and supply the list-argument twice. (or refer to it twice, using a FORMAT() construct)
first of all i would recommend you to use updated SQL from #wildplasser - it's much better and more efficient way to do that.
now you can do the following:
sql_ = """\
WITH zt AS (
SELECT * FROM ztable
WHERE id IN ({})
)
SELECT a.*, b.* -- or whatever
, st_distance(a.the_geom, b.the_geom, true) AS dist
FROM zt a
JOIN zt b ON a.nid < b.nid
"""
sampList = (14070,11184)
sql = sql_.format(','.join(['?' for x in sampList]))
df = pd.read_sql(sql, con=conn, params=sampList)
dynamically generated SQL with parameters (AKA: prepared statements, bind variables, etc.):
In [27]: print(sql)
WITH zt AS (
SELECT * FROM ztable
WHERE id IN (?,?)
)
SELECT a.*, b.* -- or whatever
, st_distance(a.the_geom, b.the_geom, true) AS dist
FROM zt a
JOIN zt b ON a.nid < b.nid