This question already has answers here:
How delete table inner join with other table in Sqlite?
(2 answers)
Closed 6 years ago.
Why am I getting an error with this statement?
Error: could not prepare statement (1 near "t3": syntax error)
(Note: tables renamed for simplicity)
DELETE FROM table3 t3
INNER JOIN table2 t2 ON t2.tempId = t3.tempId
INNER JOIN table1 t1 ON t1.tempId = t2.tempId
WHERE t1.tempId = 9;
"Heh ..." I don't think that the DELETE statement knows anything about "joins" ...
... and I sure-as-heck think that I understand *why (not)."
Instead, do this:
Start a transaction.
Run a SELECT query to obtain a list of record-IDs that meet your
selection criteria.
"Aww, heck ..." Go ahead and dump a list of those record-IDs to some log-file somewhere ....
Execute a series of DELETE queries to delete these IDs.
COMMIT. (Or, if anything-at-all goes wrong, ROLLBACK.)
Related
I have a database A.db, which contains tables t1, t2 and t3.
Now I want to create a new database B.db, which contains t1 and some chosen columns col1 and col4 from t2.
With .import I get hundreds of errors and it seems to work only for full tables.
.output sounds like I just save the output as it would be printed.
Basically, I need an insert into foo select ... across different files. How can I do this?
First you must attach A.db to your current database and give it an alias like adb.
Then write the insert statement just like you would if all the tables existed in the same database, qualifying the column names with the database alias.
It's a good practice to include in the insert into... statement inside parentheses all the column names of the table foo for which you will set values from the other 2 tables, but also be sure that the order of the columns is the same with the order of the columns in the select list:
attach database 'pathtoAdatabase/A.db' as adb;
insert into foo (column1, column2, .......)
select adb.t1.column1, adb.t1.column2, ...., adb.t2.col1, adb.t2.col4
from adb.t1 inner join adb.t2
on <join condition>
Replace <join condition> with the conditions on whichyou will join the 2 tables to makes the rows that you will insert into foo, something like:
adb.t1.id = adb.t2.id
This question already has answers here:
Overwrite only some partitions in a partitioned spark Dataset
(3 answers)
Closed 4 years ago.
I'm using the spark_write_table function from sparklyr to write tables into HDFS, using the partition_by parameter to define how to store them:
R> my_table %>%
spark_write_table(.,
path="mytable",
mode="append",
partition_by=c("col1", "col2")
)
However, now I want to update the table by altering just one partition, instead of writing the whole table again.
In Hadoop-SQL I would do something like:
INSERT INTO TABLE mytable
PARTITION (col1 = 'my_partition')
VALUES (myvalues..)
Is there an equivalent option to do this in sparklyr correctly? I cannot find it in the documentation.
Re - duplication note: this question is specifically about the way to do this in R with the sparklyr function, while the other question is about general Hive syntax
Thanks all for the comments.
It seems there is no way to do this with sparklyr directly, but this is what I am going to do.
In short, I'll save the new partition file in a temporary table, use Hadoop SQL commands to drop the partition, then another SQL command to insert into the temporary table into it.
> dbGetQuery(con,
"ALTER TABLE mytable DROP IF EXISTS PARTITION (mycol='partition1');")
> spark_write_table(new_partition, "tmp_partition_table")
> dbGetQuery(con,
"INSERT VALUES INTO TABLE mytable
PARTITION (mycol='partition1')
SELECT *
FROM tmp_partition_table "
)
I have a SQLite table where one column contains a JSON array containing 0 or more values. Something like this:
id|values
0 |[1,2,3]
1 |[]
2 |[2,3,4]
3 |[2]
What I want to do is "unfold" this into a list of all distinct values contained within the arrays of that column.
To start, I am using the JSON1 extension's json_each function to extract a table of values from a row:
SELECT
value
FROM
json_each(
(
SELECT
values
FROM
my_table
WHERE
id == 2
)
)
Where I can vary the id (2, above) to select any row in the table.
Now, I am trying to wrap this in a recursive CTE so that I can apply it to each row across the entire table and union the results. As a first step I replicated (roughly) the results from above as follows:
WITH RECURSIVE result AS (
SELECT null
UNION ALL
SELECT
value
FROM
json_each(
(
SELECT
values
FROM
my_table
WHERE
id == 2
)
)
)
SELECT * FROM result;
As the next step I had originally planned to make id a variable and increment it (in a similar manner to the first example in the documentation, but haven't been able to get that to work.
I have gone through the other examples in the documentation, but they are somewhat more complex and I haven't been able to distill those down to see how they might apply to this problem.
Can someone provide a simple example of how to solve this (or a similar problem) with a recursive CTE?
Of course, my goal is to solve the problem with or without CTEs so Im also happy to hear if there is a better way...
You do not need a recursive CTE for this.
To call json_each for multiple source rows, use a join:
SELECT t1.id, t2.value
FROM my_table AS t1
JOIN json_each((SELECT "values" FROM my_table WHERE id = t1.id)) AS t2;
I want to make a volatile table using teradata.
In the select statement I am using multiple columns from different tables.
However, some of the columns in the different tables have same names.
Therefore, I am getting a 'duplication column error'.
The question is - is there any workaround to bypass this error?
Is it possible to add for example table name to column name?
This is how my code looks:
CREATE MULTISET VOLATILE TABLE test
AS (
SEL *
FROM Table_A Left JOIN Table_B
...
)
WITH DATA
ON COMMIT PRESERVE ROWS
Instead of doing a select * , select individual column names and put aliases next to it. This will bypass the error.
A select all statement only works if you're working off one table. If you're retrieving all data from multiple tables, you've to specify that in your select statement.
CREATE MULTISET VOLATILE TABLE test AS
(
SELECT Table_A.*
, Table_B.*
FROM Table_A
LEFT JOIN Table_B ON ...
...
)
WITH DATA PRIMARY INDEX(«PI»)
ON COMMIT PRESERVE ROWS
This question already has answers here:
Does SQLite support "delete from from"
(2 answers)
Closed 8 years ago.
I am performing this SQLite command:
DELETE FROM t1027 INNER JOIN translationsmain ON t1027.textid=translationsmain.textid WHERE translationsmain.osb=0
The column "textid" exists both in the table "t1027" and in "translationsmain".
The column "osb" only exists in "translationsmain".
I am getting a syntax error, but I am not sure why.
I am getting a syntax error, but I am not sure why.
Simply, because such syntax is not allowed by SQLite.
Use this syntax, instead:
DELETE FROM t1027 WHERE textid IN (SELECT textid FROM translationsmain WHERE osb = 0)