SQL Select Data From Row If Exists Else Create Row

Question

I have come across quite a few questions reguarding SQL SELECT IF EXISTS but I am unable to piece together exactly what I need.

What I am trying to do is select specific data from a row in one table if that row exists, otherwise create the row with default values, and do it all in one query to the database.

I am able to create the row in the database if it does not already exist, and if it does exist then select the data from the row, but I want to combine the latter two if at all possible.

So, instead of this: 1, check if row exists using SELECT 2, if row does not exist INSERT 3, if row does exist SELECT again to grab data

I would like to do: 1, check if row exists using select, if row does exist grab the data all in the same query 2, if row does not exist insert row

I hope I explained it properly, and thank you all for the assistance it is greatly appreciated!

you can go for insert if not exist if you want update and refer record which updated please refer :http://stackoverflow.com/questions/3164505/mysql-insert-record-if-not-exists-in-table — shola, Dec 27 '13 at 11:49
I do not want to update the record if it already exists, I want to load it, but thats not the issue, the issue is I dont want to use two select calls, I want to check if the data exists AND grab it all in the same select function. Not sure if this is even possible. — KKlouzal, Dec 27 '13 at 14:43

score 1 · Accepted Answer · answered Dec 27 '13 at 11:28

1

Not entirely sure what the problem is here. Surely all you want (in pseudocode) is:

qry ← execute("SELECT * FROM table WHERE ... FOR UPDATE")

if numrows(qry) > 0 then
  row ← fetchdata(qry)
else
  execute("INSERT INTO table VALUES (...)")
  row ← ... // inserted data
end if

// use row

answered Dec 27 '13 at 11:28

eggyal

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Yes I believe this is what I want, to not have to use two select calls, be able to check if the row exists AND grab the data all in the same select call. :) – KKlouzal Dec 27 '13 at 14:45
@user3052750: So, what's the problem? – eggyal Dec 27 '13 at 15:10
Your psudocode makes sense, I dont know how to store a querey in a variable to use it twice :) – KKlouzal Dec 27 '13 at 16:10
@user3052750: That is a problem that has very little to do with MySQL and a great deal to do with the code through which you access it. What language/libraries/frameworks/tools are you using? – eggyal Dec 27 '13 at 16:58
I'm using lua, which allows the full range of sql syntax, I just don't know if theres a way to create a variable with sql that will hold the select query, if so thats exactly what I need! – KKlouzal Dec 27 '13 at 18:36
@user3052750: This has nothing to do with SQL syntax, least of all "*creating a variable with SQL*". I don't know lua, but it is within *an lua variable* that you need to store your resultset. – eggyal Dec 27 '13 at 18:42

score 0 · Answer 2 · answered Dec 27 '13 at 11:33

0

IF Not EXISTS (SELECT * FROM ------)
BEGIN
    --Insert HERE
END
ELSE
BEGIN
   --  select HERE
END

answered Dec 27 '13 at 11:33

Nagaraj S

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SQL Select Data From Row If Exists Else Create Row

2 Answers2