CODEWITHSUNDEEP
mysqlgostored-procedures
gfish3000
gfish3000

Reputation: 1567

Can't retrieve output parameter with Go MySQL

I have a stored procedure which inserts an entity and returns its new UUID, and while I can generate the code to create the right query, it errors out when using go-sql-driver/mysql. So the following code...

func test_insert() *sql.Rows {
    db := openDbConnection()

    defer db.Close()

    results, err := db.Query("call saveargument(null, 'Test Argument', 'Test Argument', '1', null, null, null, 1, 'test_user', @newargumentid);\nselect @newargumentid;")

    toolkit.HandleError(err)

    return results
}

func openDbConnection() *sql.DB {
    var db, err = sql.Open("mysql", getConnectionString(entities.GetConfig()))

    toolkit.HandleError(err)

    return db
}

... produces the following error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select @newargumentid' at line 2

I'm not sure why such a basic piece of SQL could be so problematic. Any insights anyone?

Upvotes: 2

Views: 1663

Answers (2)

Jans Rautenbach
Jans Rautenbach

Reputation: 469

I just tested @Bill's answer and I can confirm it does not work as at Go1.14. My workaround was to rewrite my stored procedure to "return" values by doing a select at the end:

CREATE PROCEDURE foo()
BEGIN
    # do stuff...

    SELECT 'bar';
END;

And then in Go just read it like any other query:

res, _ := db.Query("CALL foo()")
res.Next()
var bar string
res.Scan(&bar)
println(bar)

Note this method also works for multiple columns and multiple rows.

Upvotes: 0

Bill Karwin
Bill Karwin

Reputation: 562260

You can't run more than one statement in a single db.Query() call. This is true of most query interfaces in all programming languages.

Call your stored procedure in one call to db.Query(), then query select @newargumentid in a second call to db.Query().

Upvotes: 3

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