SQL IF exist date by day do increment update else insert data - mysql

Question

How can I express the below statement as a SQL query ?
IF EXISTS (SELECT * FROM expense_history
WHERE user_id = 40
AND DATE_FORMAT(expense_history.created_date , '%Y-%m-%d') = '2018-06-02'
AND camp_id='80')
UPDATE expense_history
SET clicks = clicks + 1,
amount = amount + 1
WHERE user_id = 40
AND DATE_FORMAT(expense_history.created_date, '%Y-%m-%d') = '2018-06-02'
AND camp_id = '80'
ELSE
INSERT INTO expense_history (camp_id, created_date, amount, user_id)
VALUES ('80', '2018-06-02 12:12:12', '1', '40')
END IF;
I just want to do increment clicks and amount if is set by day, else I want to add new row.

Answer 1

This is very tricky in MySQL. You are storing a datetime but you want the date part to be unique.
Starting in MySQL 5.7.?, you can use computed columns for the unique constraint. Here is an example:
create table expense_history (
user_id int,
camp_id int,
amount int default 0,
clicks int default 1,
. . .
created_datetime datetime, -- note I changed the name
created_date date generated always as (date(created_datetime)),
unique (user_id, camp_id, created_datetime)
);
You can then do the work as:
INSERT INTO expense_history (camp_id, created_datetime, amount, user_id)
VALUES (80, '2018-06-02 12:12:12', 1, 40)
ON DUPLICATE KEY UPDATE
amount = COALESCE(amount + 1, 1),
clicks = COALESCE(clicks + 1, 1);
Earlier versions of MySQL don't support generated columns. Nor do they support functions on unique. But you can use a trick on a prefix index on a varchar to do what you want:
create table expense_history (
user_id int,
camp_id int,
amount int default 0,
clicks int default 1,
. . .
created_datetime varchar(19),
unique (created_datetime(10))
);
This has the same effect.
Another alternative is to store the date and the time in separate columns.

Answer 2

I presumed your database is mysql, because of DATE_FORMAT() function(and edited your question as to be).
So, by using such a mechanism below, you can do what you want,
provided that a COMPOSITE PRIMARY KEY for camp_id, amount, user_id columns :
SET #camp_id = 80,
#amount = 1,
#user_id = 40,
#created_date = sysdate();
INSERT INTO expense_history(camp_id,created_date,amount,user_id,clicks)
VALUES(#camp_id,#created_date,#amount,#user_id,ifnull(clicks,1))
ON DUPLICATE KEY UPDATE
amount = #amount + 1,
clicks = ifnull(clicks,0)+1;
SQL Fiddle Demo