I'm trying to get all columns from each table with a prefix in the output, without mentioning all column names specifically in the select statement. Like:
SELECT *
FROM TABLE1 as T1
FULL JOIN TABLE2 as T2
ON T1.number=T2.number
Where I would want to get all column names from table1 and table2 prefixed with "T1" and "T2".
Many thanks in advance!
SELECT
CONCAT('T1', COLUMN_NAME), ORDINAL_POSITION
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'TABLE1'
ORDER BY 2
UNION
SELECT CONCAT('T2', COLUMN_NAME), ORDINAL_POSITION
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'TABLE2'
ORDER BY 2
Related
I'm currently using StandardSQL in BigQuery, I tried to join two sets of table one of which is a pseudo-column table partitioned by day.
I tried to use this query below:
SELECT
DISTINCT DATE(create_time) AS date,
user_id,
city_name,
transaction_id,
price
FROM
table_1 a
LEFT JOIN (SELECT user_id, city_name FROM table_2) b
ON (a.user_id = b.user_id AND DATE(create_time) = _PARTITIONDATE)
I've tried this kind of JOIN (using _PARTITIONDATE) and worked out, but for this particular query I got an error message:
Unrecognized name: _PARTITIONDATE
Can anyone tell me why this happened, and how could I solve this? Thanks in advance.
The issue is that you are not selecting the _PARTITIONDATE field from table_2 when joining it so it can't recognize it:
SELECT user_id, city_name FROM table_2
In order to solve it you can add it as follows:
SELECT
DISTINCT DATE(create_time) AS date,
user_id,
city_name,
transaction_id,
price
FROM
table_1 a
LEFT JOIN (SELECT _PARTITIONDATE AS pd, user_id, city_name FROM table_2) b
ON (a.user_id = b.user_id AND DATE(create_time) = pd)
Note that you'll need an alias such as pd as it's a pseudocolumn
Probably it was working in the past if you were joining two tables directly such as in (you don't get selectivity benefits in that case):
FROM
table_1 a
LEFT JOIN table_2 b
ON (a.user_id = b.user_id AND DATE(create_time) = _PARTITIONDATE)
I am trying to join two tables:
select * from
(select *, STRING(ID) as ID_string from Dataset1.Table1 where create_date >= 1388514600) as A left join each Dataset2.Table1 as B on A.ID_string = B.ID
On running the above query, I get the following error:
Field 'ID_string' not found in table 'Dataset1.Table1'
Why is the join not recognizing the newly created column "ID_string"?
Solution: Try the same query, but specifying each field by its name (instead of using *).
When joining two tables on a varchar column wrapped in a upper statement, the join does not work if there is a trailing space in both of the varchar values.
In the two examples below, VALUE1 and VALUE2 = 'ABC '
-- Doesn't work
SELECT * FROM TABLE1 INNER JOIN TABLE2
ON UPPER(VALUE1) = UPPER(VALUE2)
-- Works
SELECT * FROM TABLE1 INNER JOIN TABLE2
ON UPPER(TRIM(VALUE1)) = UPPER(TRIM(VALUE2))
Has anyone else run into this problem?
Let's see:
CREATE TABLE table1(value1 varchar(10));
CREATE TABLE table2(value2 varchar(10));
INSERT INTO table1 values('ABC ');
INSERT INTO table2 values('ABC ');
SELECT * FROM TABLE1 INNER JOIN TABLE2
ON UPPER(VALUE1) = UPPER(VALUE2)
Result:
value1 | value2
--------+--------
ABC | ABC
It appears to work.
Make sure you don't use the CHAR(N) type instead of VARCHAR(N), since they have different semantics concerning spaces.
I wrote a stored procedure with a table name as parameter, that checks if there are duplicate rows in this table. The statements are built dynamically of course:
INSERT INTO tmpTable
SELECT col1, col2,... FROM table GROUP BY col1, col2, ... HAVING COUNT(*) > 1;
DELETE FROM tablename FROM tablenname
INNER JOIN tmpTable ON ISNULL(tablename.col1, 0) = ISNULL(tmpTable.col1, 0)
AND ISNULL(tablename.col2, 0) = ISNULL(tmpTable.col2, 0)
AND ...;
INSERT INTO tablename SELECT * FROM tmpTable;
Should work so far, but problem is, that it fails when the table has blob columns, like text. Those can not be compared in the JOIN. I also tried
DELETE FROM tablename GROUP BY col1, col2, ... HAVING COUNT(*) > 1;
but GROUP BY is not supported in DELETE statement directly without self-joining.
Also it's not possible to query information_schema for primary key of this table, since none of these tables has one.
Any ideas? Thanks.
Since the statement is already built dynamically, add casting the relevant columns to varchar(max) for the purpose of join. It's not difficult to figure which columns that are:
select c.name, quotename(c.name, '[')
from
sys.columns c
inner join sys.types t on c.system_type_id = t.system_type_id
where
c.object_id = object_id(#TABLE_NAME)
and c.is_computed = 0
and t.name in ('text', 'image', 'timestamp', 'xml')
I have three tables table1 (main table), table2, table3.
table1 contains table1Id
table2 and table3 contain table2Id, table2RoleId, table3Id, table3RoleId.
Also the same value of table1Id, more than one record in table2Id and table3Id but the table2RoleId's and table3RoleId's are different.
I want to join table1 with table2 and table3 to display like
Table2RoleId and Table3RoleId has to display according to the Table1Id
How can I achieve this?
Thanks
i'm ignore the content of your question and will show you sample left join in linq
var result = from x in table1 join y in table2
on x.tableId1 equals y.tableId1
join z in table3 on x.tableId1 equals z.tableId1
Select new {// your return fields}