Develop Reference

Insert into SQLite database if not exist in Java [duplicate]

I have an SQLite database. I am trying to insert values (users_id, lessoninfo_id) in table bookmarks, only if both do not exist before in a row.
INSERT INTO bookmarks(users_id,lessoninfo_id)
VALUES(
(SELECT _id FROM Users WHERE User='"+$('#user_lesson').html()+"'),
(SELECT _id FROM lessoninfo
WHERE Lesson="+lesson_no+" AND cast(starttime AS int)="+Math.floor(result_set.rows.item(markerCount-1).starttime)+")
WHERE NOT EXISTS (
SELECT users_id,lessoninfo_id from bookmarks
WHERE users_id=(SELECT _id FROM Users
WHERE User='"+$('#user_lesson').html()+"') AND lessoninfo_id=(
SELECT _id FROM lessoninfo
WHERE Lesson="+lesson_no+")))
This gives an error saying:
db error near where syntax.

If you never want to have duplicates, you should declare this as a table constraint:
CREATE TABLE bookmarks(
users_id INTEGER,
lessoninfo_id INTEGER,
UNIQUE(users_id, lessoninfo_id)
);
(A primary key over both columns would have the same effect.)
It is then possible to tell the database that you want to silently ignore records that would violate such a constraint:
INSERT OR IGNORE INTO bookmarks(users_id, lessoninfo_id) VALUES(123, 456)

If you have a table called memos that has two columns id and text you should be able to do like this:
INSERT INTO memos(id,text)
SELECT 5, 'text to insert'
WHERE NOT EXISTS(SELECT 1 FROM memos WHERE id = 5 AND text = 'text to insert');
If a record already contains a row where text is equal to 'text to insert' and id is equal to 5, then the insert operation will be ignored.
I don't know if this will work for your particular query, but perhaps it give you a hint on how to proceed.
I would advice that you instead design your table so that no duplicates are allowed as explained in #CLs answer below.

For a unique column, use this:
INSERT OR REPLACE INTO tableName (...) values(...);
For more information, see: sqlite.org/lang_insert

insert into bookmarks (users_id, lessoninfo_id)
select 1, 167
EXCEPT
select user_id, lessoninfo_id
from bookmarks
where user_id=1
and lessoninfo_id=167;
This is the fastest way.
For some other SQL engines, you can use a Dummy table containing 1 record.
e.g:
select 1, 167 from ONE_RECORD_DUMMY_TABLE

Merge and When Matched query giving an error sql server

I have a query which I am trying to test. The query should update the data if it finds data in the table with existing primary key. If it doesn't then insert into the table.
The Primary key is of type int and in the properties I can see Identity is set to "True" which I assume it means that it will automatically set the new id for the primary if it is inserted.
MERGE INTO Test_table t
USING (SELECT 461232 ID,'Test1-data' Fascia FROM Test_table) s
ON (t.ID = s.ID)
WHEN MATCHED THEN
UPDATE SET t.Fascia = s.Fascia
WHEN NOT MATCHED THEN
INSERT (Fascia)
VALUES (s.Fascia);
The issue here is this query doesn't work and it never inserts the data or updates. Also, query gets compiled and I don't get any compilation error
Also the reason I want this query is to work because then I will use Java prepared statement to query the database so I am assuming I can do
SELECT ? ID,? Fascia FROM Test_table
So that I can pass the values with set methods in java.
Please let me know if there is something wrong in my query.

You are selecting from the target table as your source.
You either need to remove your FROM Test_table or have at least 1 row in Test_table prior to your merge.
rextester demo: http://rextester.com/XROJD28508
MERGE INTO Test_table t
USING (SELECT 461232 ID,'Test1-data' Fascia --FROM Test_table
) s
ON (t.ID = s.ID)
WHEN MATCHED THEN
UPDATE SET t.Fascia = s.Fascia
WHEN NOT MATCHED THEN
INSERT (Fascia)
VALUES (s.Fascia);

MySQL inserting data while only knowing 1 column name

I am wanting to insert some data into a MySQL table, these are the columns:
uuid | id_1 | id_41
the "id_1" and "id_41" could be anything, all I know is the primary key (uuid) and I am wanting to be able to insert into the table while only knowing the uuid column value as I am doing this so far:
PreparedStatement newPlayer = "INSERT INTO `test` values(?);";
newPlayer.setString(1, event.getPlayer().getUniqueId().toString());
But when I test it, it doesn't add to the table and does not produce any errors. I also know that all of the other values have a default value of 0

If you want to add a row without all columns included, you need to specify the column's name
INSERT INTO `test` (`uuid`) values(?);

Simple tell to insert the column you want insert eg for uuid
INSERT INTO `test` ( `uuid`) values(?);

"Invalid Column id" error when counting unique value in Java

I am using the following sql query in my java program:
SELECT COUNT(*) FROM event WHERE externaleventid ='1256294';
But I have an error as:
Invalid Column id.
Same query works fine in SQL Developer.

For some reason you are attempting to get a column named "externaleventid" from the query, but only "count(*)" is available. You shouldn't try to get back the where clause bind variables from the result set, you should get the actual data back from the result set, by column index or by column name.
Try rs.getInt(1) to get the data from the first column. Or, you can alias the column in the query, e.g. SELECT count(*) cnt FROM..., and you can refer to it by the aliased column name: rs.getInt("cnt").

INSERT INTO SELECT STATEMENT with multiple FK

This is my code with 1 FK.
here's the columns
([PK]charityRoomID, charityRoomStatus, [FK]charityWardID)
INSERT INTO tbl_addcharityroom1 (charityRoomStatus, charityWardID)
VALUES ('"+jTextField10aw.getText() +"', (
select charityWardID
from tbl_addcharityward
where diseaseCategory='"+ jComboBox1.getSelectedItem().toString() +"'))";
Now, I added a new column(RateID) which is another FK, but i don't know the correct statement for multiple FK. here's the columns
([PK]charityWardID, charityRoomStatus, [FK]charityWardID, [FK]rateID)
I am using netbeans & mySQL

A FK is just a constraint on a database column. It basically means that your column content must map to a specified column when you insert data.
So, if your insert statement specifies a value that exist in the ID column of your Rate table, everything will be allright. Otherwise, an exception will occur.
Basically you just need to do this, replacing "yourRateIdValue" by an Id that actually exist in your Rate table:
"INSERT INTO tbl_addcharityroom1 (charityRoomStatus, charityWardID, rateID)
VALUES ('" + jTextField10aw.getText() + "', (
select charityWardID
from tbl_addcharityward
where diseaseCategory='"+ jComboBox1.getSelectedItem().toString() +"'), yourRateIdValue)";
You can also replace the "yourRateIdValue" by a select statement, as you did for the "charityWardID" column