Question

This query appears to work well:

-- Every supplier that produces some red or green part
SELECT Suppliers.sid
FROM Suppliers, Catalog, Parts
WHERE Suppliers.sid = Catalog.sid 
    AND Catalog.pid = Parts.pid
    AND (Parts.color = "red" OR Parts.color = "green");

To check it, I’d like to look at every SID that will not be returned by this query, to make sure that they do not produce green or red parts. How can I do this?

This doesn’t seem to be working:

SELECT Parts.color
FROM Suppliers, Catalog, Parts
WHERE Suppliers.sid NOT IN (    
    SELECT Suppliers.sid, Parts.color
    FROM Suppliers, Catalog, Parts
    WHERE Suppliers.sid = Catalog.sid 
        AND Catalog.pid = Parts.pid
        AND (Parts.color = "red" OR Parts.color = "green")
    );

MySQL Error:

Error 1241 (21000): Operand should
contain 1 column(s)

What is the right way to go about this?

This is the SQL used to create the tables I’m working with:

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL';

CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ;
USE `mydb`;

-- -----------------------------------------------------
-- Table `mydb`.`Suppliers`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `mydb`.`Suppliers` (
  `sid` INT NOT NULL ,
  `sname` VARCHAR(45) NULL ,
  `address` VARCHAR(45) NULL ,
  PRIMARY KEY (`sid`) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`Parts`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `mydb`.`Parts` (
  `pid` INT NOT NULL ,
  `pname` VARCHAR(45) NULL ,
  `color` VARCHAR(45) NULL ,
  PRIMARY KEY (`pid`) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`Catalog`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `mydb`.`Catalog` (
  `cost` INT NULL ,
  `pid` INT NOT NULL ,
  `sid` INT NOT NULL ,
  PRIMARY KEY (`pid`, `sid`) ,
  INDEX `fk_Catalog_Parts1` (`pid` ASC) ,
  INDEX `fk_Catalog_Suppliers1` (`sid` ASC) ,
  CONSTRAINT `fk_Catalog_Parts1`
    FOREIGN KEY (`pid` )
    REFERENCES `mydb`.`Parts` (`pid` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_Catalog_Suppliers1`
    FOREIGN KEY (`sid` )
    REFERENCES `mydb`.`Suppliers` (`sid` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;



SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

Answer 1

NOt completely knowing what you are getting at I see a couple of things wrong. First remove the second column inthe subquery, it is unnecessary:

SELECT Parts.color 
FROM Suppliers, Catalog, Parts 
WHERE Suppliers.sid NOT IN (     
    SELECT Suppliers.sid    FROM Suppliers, Catalog, Parts 
    WHERE Suppliers.sid = Catalog.sid  
        AND Catalog.pid = Parts.pid 
        AND (Parts.color = "red" OR Parts.color = "green") 
    ); 

Finally you apear to have a cross join which I supect you don’t want. This is a classic example of why you should not use implicit joins. See if this might work better:

SELECT Parts.color 
FROM Suppliers 
JOIN Catalog  on Suppliers.sid = Catalog.sid  
JOIN  Parts on Catalog.pid = Parts.pid 
WHERE Suppliers.sid NOT IN (     
    SELECT Suppliers.sid
    FROM  Suppliers 
    JOIN Catalog  on Suppliers.sid = Catalog.sid  
    JOIN  Parts on Catalog.pid = Parts.pid 
       WHERE (Parts.color = "red" OR Parts.color = "green") 
    );