Insert into a MySQL table or update if exists

Check out REPLACE:

REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted.

Example:

REPLACE INTO `tablename` (`id`, `name`, `age`) VALUES (1, "A", 19)

When using batch insert use the following syntax:

INSERT INTO TABLE (id, name, age) VALUES (1, "A", 19), (2, "B", 17), (3, "C", 22)
ON DUPLICATE KEY UPDATE
    name = VALUES (name),
    ...

Any of these solution will work regarding your question:

INSERT IGNORE INTO table (id, name, age) VALUES (1, "A", 19);

or

INSERT INTO TABLE (id, name, age) VALUES(1, "A", 19) 
    ON DUPLICATE KEY UPDATE NAME = "A", AGE = 19;  

or

REPLACE INTO table (id, name, age) VALUES(1, "A", 19);

Try this:

INSERT INTO table (id,name,age) VALUES('1','Mohammad','21') ON DUPLICATE KEY UPDATE name='Mohammad',age='21'

Note:
Here if id is the primary key then after first insertion with id='1' every time attempt to insert id='1' will update name and age and previous name age will change.

Try this out:

INSERT INTO table (id, name, age) VALUES (1, 'A', 19) ON DUPLICATE KEY UPDATE id = id + 1;

Hope this helps.

In case that you wanted to make a non-primary fields as criteria/condition for ON DUPLICATE, you can make a UNIQUE INDEX key on that table to trigger the DUPLICATE.

ALTER TABLE `table` ADD UNIQUE `unique_index`(`name`);

And in case you want to combine two fields to make it unique on the table, you can achieve this by adding more on the last parameter.

ALTER TABLE `table` ADD UNIQUE `unique_index`(`name`, `age`);

Note, just make sure to delete first all the data that has the same name and age value across the other rows.

DELETE table FROM table AS a, table AS b WHERE a.id < b.id 
AND a.name <=> b.name AND a.age <=> b.age;

After that, it should trigger the ON DUPLICATE event.

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE    
name = VALUES(name), age = VALUES(age)

Just because I was here looking for this solution but for updating from another identically-structured table (in my case website test DB to live DB):

INSERT  live-db.table1
SELECT  *
FROM    test-db.table1 t
ON DUPLICATE KEY UPDATE
        ColToUpdate1 = t.ColToUpdate1,
        ColToUpdate2 = t.ColToUpdate2,
        ...

As mentioned elsewhere, only the columns you want to update need to be included after ON DUPLICATE KEY UPDATE.

No need to list the columns in the INSERT or SELECT, though I agree it's probably better practice.

When using SQLite:

REPLACE into table (id, name, age) values(1, "A", 19)

Provided that id is the primary key. Or else it just inserts another row. See INSERT (SQLite).

In case, you want to keep old field (For ex: name). The query will be:

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE    
name=name, age=19;

Following are some of the possible approaches:

Using INSERT INTO

The INSERT statement allows you to insert one or more rows into a table

• First, specify the table name and a list of comma-separated columns inside parentheses after the INSERT INTO clause.
• Secondly, put a comma-separated list of values of the corresponding columns inside the parentheses following the VALUES keyword.

INSERT INTO table_name(column_name1, column_name2, column_name3) VALUES("col_value_1", "col_value_2", "col_value_3");

Using INSERT INTO with WHERE NOT EXISTS clause

INSERT INTO table_name (column_name_1, column_name_2, column_name_3)
SELECT * FROM (SELECT "col_value_1", "col_value_2","col_value_3") AS tmp_name
WHERE NOT EXISTS (
    SELECT column_name2 FROM table_name WHERE column_name = "sample_name"
) LIMIT 1;

Using REPLACE INTO

REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted.

REPLACE INTO table_name(column_name1, column_name2, column_name3) VALUES("col_value_1", "col_value_2", "col_value_3");

In my case i created below queries but in the first query if id 1 is already exists and age is already there, after that if you create first query without age than the value of age will be none

REPLACE into table SET `id` = 1, `name` = 'A', `age` = 19

for avoiding above issue create query like below

INSERT INTO table SET `id` = '1', `name` = 'A', `age` = 19 ON DUPLICATE KEY UPDATE `id` = "1", `name` = "A",`age` = 19

may it will help you ...

Here is a better way to accomplish an INSERT and UPDATE without affecting the auto increment and on top of that getting back the primary key in either scenario in a consistent way. It does involve multiple commands but can be done on one line if desired. This would be in a case where one or more fields make up a unique constraint like in this case country.

If you want the primary key back from INSERT or UPDATE only null values

SET @now=NOW();
SET @country='Example Country',@country_code='EC',@country_overview='An example country overview.';
INSERT INTO country (country, country_code, country_overview, added_at, updated_at)
SELECT @country,@country_code,@country_overview, @now, @now
FROM dual
WHERE NOT EXISTS (
    SELECT 1 FROM country WHERE country=@country
);
SELECT countryid INTO @countryid FROM country WHERE country=@country;
UPDATE country 
SET 
country_code = @country_code, 
country_overview = @country_overview, 
updated_at = @now 
WHERE countryid = @countryid AND added_at <> @now;

If you want the primary key back from INSERT or UPDATE only null values

SET @now=NOW();
SET @country='Example Country',@country_code='EC',@country_overview='An example country overview.';
INSERT INTO country (country, country_code, country_overview, added_at, updated_at)
SELECT @country,@country_code, @now, @now
FROM dual
WHERE NOT EXISTS (
    SELECT 1 FROM country WHERE country=@country
);
SELECT countryid INTO @countryid FROM country WHERE country=@country;
UPDATE country 
SET 
country_code = COALESCE(country_code, @country_code), 
country_overview = COALESCE(country_overview, @country_overview), 
updated_at = @now 
WHERE countryid = @countryid AND added_at <> @now;

There are few other ways you can work with this to get the primary key back you could do the following as your last statement.

SELECT @countryid;