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1 lut 2010 · Here's a query to update a table based on a comparison of another table. If record is not found in tableB, it will update the "active" value to "n". If it's found, will set the value to NULL. UPDATE tableA LEFT JOIN tableB ON tableA.id = tableB.id SET active = IF(tableB.id IS NULL, 'n', NULL)"; Hope this helps someone else.
14 sty 2013 · You would have to use code to determine whether the ID exists. That is fairly easy & would look like this Dim mySQL as string IF DCount("*", "tablename","ID=" & me.NameOfControlOnFormThatHoldsID)>0 THEN 'record exists, construct the update query mySQL= "UPDATE tablename SET ..." ELSE 'new record needed, construct the append query
14 kwi 2020 · Normally you would use an unmatched append query to insert the new records and an update query to modify the existing records. However in certain circumstances you can combine these into one query commonly known as an UPSERT or UPEND query.
11 kwi 2019 · I need to do and IF/THEN statement in mysql based on whether a value exists in a column. If it exists, I need to perform an update on the record and if it does not, then an error should be thrown. I want to check that the siteID actually exists. How can I add an "IF EXISTS" statement?
29 kwi 2015 · IF EXISTS (select * from users where username = 'something') THEN. update users set id= 'some' where username = 'something'; ELSE. insert into users (username) values ('something'); END IF; end $$. delimiter ; and call it like this: call select_or_insert();
16 kwi 2016 · UPDATE Tests SET TestScore = CASE WHEN TestId = 10 THEN 1000 WHEN TestId = 11 THEN 1100 END, TestScore2 = CASE WHEN TestId = 10 THEN 2000 WHEN TestId = 11 THEN 2100 END WHERE TestId IN (10, 11) But what happens when there two conditions required, namely the joint combo of (TestId, TestSubId)?
1 cze 2015 · If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row is performed. Please read URL for more details.
