I have a join SQL Request where the output of 2 tables is produced :
ss= 'Select t.*, p.* from table1 t, table1 p where t.table2_id=p.table1_id'
df = pd.read_sql_query(ss, self.db_con)
However, some columns have same name since the table is stripped.
(ex: id, id ...)
How to get table.colname in the dataframe ?
Thanks
You have to rename the conflicting columns with AS:
SELECT t.id AS t_id, p.id AS p_id, FROM table1 t, table2 p WHERE t.id = p.id
Related
I need Only one unique result from tableB.Field to tableA.Field
I am using sdo operator sdo_nn, this is the code:
UPDATE table1 t1
SET t1.fieldA = (SELECT T2.fieldB,SDO_NN_DISTANCE(1) distance
FROM table1 T1, table2 T2
WHERE
(sdo_nn(t1.geometry,t2.geometry,'SDO_NUM_RES=1',1)= 'TRUE')
ORDER BY DIST
)
WHERE EXISTS(
SELECT 1
FROM table2 t2
WHERE sdo_nn(t1.geometry, t2.geometry,'SDO_NUM_RES=1',1)='TRUE'
AND(t2.cell_name = 'string1' or t2.cell_name = string2')AND t1.fieldA = NULL
);
In the select sentence of the subquery i get an error because i only use one field(t1.fieldA), but in the sentence i use the operator SDO_NN_DISTANCE(1) and the sql developer count this operator like another field. What is the correct way to write this sentence? I only use sql because i need to insert this code in vba
Thanks!!!
Obviously, you can't (simplified)
set t1.fieldA = (t2.fieldB, distance) --> you want to put two values into a single column
Therefore, get fieldB alone from the subquery which uses analytic function (row_number) to "sort" rows by sdo_nn_distance(1) desc; then get the first row's fieldB value.
Something like this (I hope I set the parenthesis right):
UPDATE table1 t1
SET t1.fieldA =
(SELECT x.fieldB --> only fieldB
FROM (SELECT T2.fieldB, --> from your subquery
SDO_NN_DISTANCE (1) distance,
ROW_NUMBER ()
OVER (ORDER BY sdo_nn_distance (1) DESC) rn
FROM table1 T1, table2 T2
WHERE (sdo_nn (t1.geometry,
t2.geometry,
'SDO_NUM_RES=1',
1) = 'TRUE')) x
WHERE rn = 1) --> where RN = 1
WHERE EXISTS
(SELECT 1
FROM table2 t2
WHERE sdo_nn (t1.geometry,
t2.geometry,
'SDO_NUM_RES=1',
1) = 'TRUE'
AND ( t2.cell_name = 'string1'
OR t2.cell_name = 'string2')
AND t1.fieldA IS NULL);
In SQLite, I have the following query
SELECT x.nameIndex, y.nameIndex
FROM relation x, relation y
WHERE x.label=y.label AND x.feature=1 AND y.feature=0;
which returns all pairs of x.nameIndex,y.nameIndex with the same label where x has feature 1 and y has feature 0.
Now I have another table index2name where I store the name for each index, where I could do like:
SELECT name FROM index2name WHERE nameIndex=...;
How can I change the top query such that it looks up the name for the respective indeces and returns pairs of names instead?
Use a CTE which returns the name instead of the indexes and the group for each row in relation (by a join to index2name) and do a self join on that:
WITH cte AS (
SELECT i.name, r.label, r.feature
FROM relation r INNER JOIN index2name i
ON i.nameIndex = r.nameIndex
)
SELECT c1.name, c2.name
FROM cte c1 INNER JOIN cte c2
ON c2.label = c1.label
WHERE c1.feature=1 AND c2.feature=0;
Or without the CTE:
SELECT i1.name, i2.name
FROM relation r1 INNER JOIN relation r2
ON r2.label = r1.label
INNER JOIN index2name i1 ON i1.nameIndex = r1.nameIndex
INNER JOIN index2name i2 ON i2.nameIndex = r2.nameIndex
WHERE r1.feature=1 AND r2.feature=0;
I'm trying to get the result into a variable (is it possible to do it as a %rowtype of an existing table? probably not because of conflicting columns) where it would display me all the values where the two refs overlap and the i_ref(which is inputted ) also overlaps with the ref from t1.
select *
into aRow
from table1 t1
where t1.ref = i_ref
and (select * from table2 t2 where t1.ref = t2.ref);
What am I doing wrong with my select?
You can join tables instead of nested subquery:
select t1.*
into aRow
from table1 t1 join table2 t2 on t1.ref = t2.ref
where t1.ref = i_ref
just wondering how i can create a temp table and then select from it further down the script.
Example.
CREATE TEMPORARY TABLE TEMP_TABLE1 AS
Select
L.ID,
SUM(L.cost)/2 as Costs,
from Table1 L
JOIN Table2 C on L.ID = C.ID
Where C.name = 'mike'
Group by L.ID
Select
Count(L.ID)
from Table1 L
JOIN TEMP_TABLE1 TT1 on L.ID = TT1.ID;
Where L.ID not in (TT1)
And Sum(L.Cost) > TT1.Costs
Ideally I want to have a temp table then use it later in the script to reference from.
Any help would be great!
You simply refer to the table as temp.<table> or <table> the latter only if it is a unique table name.
As per :-
If a schema-name is specified, it must be either "main", "temp", or
the name of an attached database. In this case the new table is
created in the named database. If the "TEMP" or "TEMPORARY" keyword
occurs between the "CREATE" and "TABLE" then the new table is created
in the temp database. It is an error to specify both a schema-name and
the TEMP or TEMPORARY keyword, unless the schema-name is "temp". If no
schema name is specified and the TEMP keyword is not present then the
table is created in the main database.
SQL As Understood By SQLite - CREATE TABLE
The following example creates 3 tables :-
table1 with 3 columns as a permanent table.
table1 a temporary copy of the permanent table1.
temp_table another temporary copy of the permanent table1.
:-
DROP TABLE IF EXISTS temp.table1;
DROP TABLE IF EXISTS table1;
DROP TABLE IF EXISTS temp_table;
CREATE TABLE table1 (columnA INTEGER,columnB INTEGER, columnC INTEGER);
When creating the permanent table 1 it is loaded with 4 rows
:-
INSERT INTO table1 (columnA,columnB,columnC) VALUES
(1,5,20),
(2,7,21),
(3,8,80),
(4,3,63);
CREATE TEMP TABLE table1 AS select * from table1;;
CREATE TEMPORARY TABLE temp_table AS SELECT * FROM table1;
both temp tables are then used to in a union all to basically duplicate the rows, but with an indicator of the source table as a new column from_table
Not that two forms of referring to the temp tables are used. temp. and just the table name.
The latter only usable if the temporary table is a unique table name.
:-
SELECT 'temp_table' AS from_table,* FROM temp_table
UNION ALL
SELECT 'temp.table1' as from_table,* FROM temp.table1;
The result being :-
Re addition of example :-
CREATE TEMPORARY TABLE TEMP_TABLE1 AS
Select
L.ID,
SUM(L.cost)/2 as Costs,
from Table1 L
JOIN Table2 C on L.ID = C.ID
Where C.name = 'mike'
Group by L.ID
Select
Count(L.ID)
from Table1 L
JOIN TEMP_TABLE1 TT1 on L.ID = TT1.ID;
Where L.ID not in (TT1)
And Sum(L.Cost) > TT1.Costs
There are a few issues with this example bar the misuse of the aggregate (commented out) the following works.
Note for my convenience I've added an _ to the table names.
:-
DROP TABLE IF EXISTS Table_1;
DROP TABLE IF EXISTS Table_2;
DROP TABLE If EXISTS temp.temp_table1;
CREATE TABLE Table_1 (ID INTEGER PRIMARY KEY, cost REAL);
CREATE TABLE Table_2 (ID INTEGER PRIMARY KEY, name TEXT);
INSERT INTO Table_1 (cost) VALUES (100.45),(56.78),(99.99);
INSERT INTO Table_2 (name) VALUES ('mike'),('mike'),('fred');
CREATE TEMP TABLE temp_table1 AS
SELECT L.ID,
sum(L.cost)/2 as Costs
FROM Table_1 L
JOIN Table_2 C ON L.ID = C.ID
WHERE C.name = 'mike'
GROUP BY L.ID;
SELECT
count(L.ID)
FROM Table_1 L
JOIN temp_table1 TT1 ON L.ID = TT1.[L.ID]
WHERE
L.ID NOT IN (TT1.[L.ID])
-- AND Sum(L.cost) > TT1.costs --<<<< misuse of aggregate
The issues are based upon the column name being L.ID so this has to be enclosed (rules here SQL As Understood By SQLite - SQLite Keywords apply) [ and ] have been used above.
of course you could circumvent the need for enclosure by naming the column using AS e..g SELECT
L.ID AS lid, --<<<< AS lid ADDED
SUM(L.cost)/2 as Costs, ,.......
Adding the following may be suitable for getting around the misuse of aggregate :-
GROUP BY L.ID
HAVING sum(L.cost) > TT1.costs
Adding the following to the end of the script :-
SELECT
count(L.ID), *
FROM Table_1 L
JOIN temp_table1 TT1 ON L.ID = TT1.[L.ID];
results in :-
If this is only to be used by one SELECT statement then you can use the WITH clause:
WITH TmpTable(id,cost) AS
(
...SELECT statement that returns the two columns (id and cost)...
)
SELECT id, cost FROM TmpTable WHERE ...;
I have a very strange problem when I do the following join on two different tables in Teradata. It does not return any results, indicating that there is no common value between table_A and table_B.
SELECT
*
FROM
table_A a JOIN table_B b ON a.id = b.id;
<>
0 rows returned
However when I run the following two queries, I do get results indicating that the id column in both the tables has at least one row with 'John'.
SELECT
id
FROM table_A
WHERE
id = 'John';
<>
1 row returned
SELECT
id
FROM table_B
WHERE
id = 'John';
<>
1 row returned
The data type for all the columns in table_A and table_B is null
Can you try using the below approach :
ON trim(UPPER(table_A.id)) = trim(UPPER(table_B.id))