What wrong with my code because there is no error but I cant run it?

Question

CREATE TABLE IF NOT EXISTS Grade (
StudentNumber VARCHAR(10) NOT NULL,
ClassNumber INT(10) NOT NULL,
Grade DOUBLE(3),
PRIMARY KEY(StudentNumber, ClassNumber),
FOREIGN KEY(StudentNumber)REFERENCES student(StudentNumber),
FOREIGN KEY(ClassNumber)REFERENCES class(ClassNumber)
)

MySQL said: Documentation

1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '), PRIMARY KEY(StudentNumber, ClassNumber), FOREIGN KEY(StudentNumber)REFERENC' at line 4

PRIMARY KEY(StudentNumber, ClassNumber) ??? As per documentation, you must use only one primary key per table. — Santhosh Arun, Jan 28 '19 at 07:07
firstly, thank you sir but isnt there a composite primary key where I'm combining two data from existed tables into a new table? — An Wan, Jan 28 '19 at 07:10
@SanthoshArun it is true. Visit here: https://stackoverflow.com/questions/217945/can-i-have-multiple-primary-keys-in-a-single-table — iminiki, Jan 28 '19 at 07:11
@Santhiosh Arun -where it is written. we can declare composite key also — Kandy, Jan 28 '19 at 07:12
@AnWan have you created your student and class tabel before running above script. — Kandy, Jan 28 '19 at 07:22
Thank you everyone, I really appreciate it and I have found the soloution — An Wan, Jan 28 '19 at 07:31

score 3 · Accepted Answer · answered Jan 28 '19 at 07:18

If you use double you have to add how many digits it should have:

CREATE TABLE IF NOT EXISTS Grade (

StudentNumber VARCHAR(10) NOT NULL,

ClassNumber INT(10) NOT NULL,

Grade DOUBLE(3, 2),

PRIMARY KEY(StudentNumber, ClassNumber),

FOREIGN KEY(StudentNumber)REFERENCES student(StudentNumber),

FOREIGN KEY(ClassNumber)REFERENCES class(ClassNumber) )

What wrong with my code because there is no error but I cant run it?

1 Answers1