MariaDB – How to Compare JSON Values in MySQL

jsonmariadbMySQL

How to compare two JSON fields in MariaDB?

MariaDB 10.2 and 10.3 – FAILS

SELECT CAST('{"q":2}' AS JSON);

Returns : SQL Error (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 'JSON)' at line 1

MySQL 5.7.19 – works OK

SELECT CAST('{"num": 1.1, "date": "2015-11-01"}' AS JSON) = CAST('{"date": "2015-11-01", "num": 1.1}' AS JSON);

Returns: 1

Source: http://rpbouman.blogspot.com/2015/11/mysql-few-observations-on-json-type.html

Other similar questions

I found this but my JSON is more complex.

Best Answer

There is not, as of 10.3.7, a native JSON type on mariadb server. JSON is only an alias for LONGBLOB for compatibility reasons with MySQL: https://mariadb.com/kb/en/library/json-data-type/

While there is a library of function to work with JSON https://mariadb.com/kb/en/library/json-functions/ (select and transform it); there isn't really a native type, so all input and output of those functions is really of type string. While you could technically implement a recursive json parser with a stored procedure, I would recommend to just read it and compare it with client libraries or other client utilities (for example, https://stackoverflow.com/questions/25851183/how-to-compare-two-json-objects-with-the-same-elements-in-a-different-order-equa ).

Despite the claims by MariaDB that it is a drop-in replacement of MySQL, because MariaDB is no longer a 100% compatible fork, functionalities that are available on one software are no longer available on the other and viceversa.

Related Solutions

Mysql – ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB

Are you sure you still have an error with the following script ?

change :

CREATE TABLE IF NOT EXISTS `mydb`.`Order_has_Product` (
  `Order_id` INT{+ NOT+} NULL,
  `Product_product_id` INT{+ NOT+} NULL,

(it work on my MySQL 5.7, I don't have any mariadb to try now)

-- MySQL Script generated by MySQL Workbench
-- Thu 12 Oct 2017 01:11:28 PM EDT
-- Model: New Model    Version: 1.0    
-- MySQL Workbench Forward Engineering

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,ALLOW_INVALID_DATES';

-- -----------------------------------------------------
-- Schema mydb
-- -----------------------------------------------------

-- -----------------------------------------------------
-- Schema mydb
-- -----------------------------------------------------
CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET utf8 ;
-- -----------------------------------------------------
-- Schema customer
-- -----------------------------------------------------
-- This schema was created for a stub table

-- -----------------------------------------------------
-- Schema customer
--
-- This schema was created for a stub table
-- -----------------------------------------------------
CREATE SCHEMA IF NOT EXISTS `customer` ;
USE `mydb` ;

-- -----------------------------------------------------
-- Table `mydb`.`Product`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `mydb`.`Product` (
  `product_id` INT NOT NULL AUTO_INCREMENT,
  `Product_name` VARCHAR(45) NULL,
  `color` VARCHAR(45) NULL,
  `cost` VARCHAR(45) NULL,
  `price` INT NULL,
  `catagory` VARCHAR(45) NULL,
  `description` VARCHAR(45) NULL,
  `stock` VARCHAR(3) NULL,
  PRIMARY KEY (`product_id`))
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`customer`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `mydb`.`customer` (
  `name` VARCHAR(45) NULL,
  `address` VARCHAR(45) NULL,
  `city` VARCHAR(45) NULL,
  `country` VARCHAR(45) NULL,
  `customer_id` VARCHAR(45) NOT NULL,
  `state` VARCHAR(2) NULL,
  `zip` INT NULL,
  `credit_card` BIGINT(17) NULL,
  PRIMARY KEY (`customer_id`))
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`Order`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `mydb`.`Order` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `price` INT NULL,
  `date` DATE NULL,
  `shipping_date` DATE NULL,
  `completed` VARCHAR(3) NULL,
  `urgent_order` VARCHAR(3) NULL,
  `vip` VARCHAR(3) NULL,
  `quantity` INT NULL,
  `product_id` INT NULL,
  `repeat_order` VARCHAR(3) NULL,
  `customer_customer_id` VARCHAR(45) NULL,
  PRIMARY KEY (`id`),
  INDEX `fk_Order_customer1_idx` (`customer_customer_id` ASC),
  CONSTRAINT `fk_Order_customer1`
    FOREIGN KEY (`customer_customer_id`)
    REFERENCES `mydb`.`customer` (`customer_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`review`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `mydb`.`review` (
  `review_id` INT NOT NULL AUTO_INCREMENT,
  `rating` INT NULL,
  `review` VARCHAR(45) NULL,
  `order_id` INT NULL,
  `date` DATE NULL,
  `Product_product_id` INT NULL,
  PRIMARY KEY (`review_id`),
  INDEX `fk_review_Product1_idx` (`Product_product_id` ASC),
  CONSTRAINT `fk_review_Product1`
    FOREIGN KEY (`Product_product_id`)
    REFERENCES `mydb`.`Product` (`product_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `mydb`.`Order_has_Product`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `mydb`.`Order_has_Product` (
  `Order_id` INT NOT NULL,
  `Product_product_id` INT NOT NULL,
  PRIMARY KEY (`Order_id`, `Product_product_id`),
  INDEX `fk_Order_has_Product_Product1_idx` (`Product_product_id` ASC),
  INDEX `fk_Order_has_Product_Order1_idx` (`Order_id` ASC),
  CONSTRAINT `fk_Order_has_Product_Order1`
    FOREIGN KEY (`Order_id`)
    REFERENCES `mydb`.`Order` (`id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE,
  CONSTRAINT `fk_Order_has_Product_Product1`
    FOREIGN KEY (`Product_product_id`)
    REFERENCES `mydb`.`Product` (`product_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;

USE `customer` ;

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

Mysql – Can MariaDB or MySQL cast as bigint, getting an error: … right syntax to use near ‘bigint)’

Silently? Let's try:

CREATE TABLE g
   AS SELECT CAST('2147483699' AS int);

MariaDB 10.1.32, default sql_mode (non-strict)

Query OK, 1 row affected, 1 warning (0.19 sec) Records: 1 Duplicates: 0 Warnings: 1

And the warning is:

| Warning | 1264 | Out of range value for column 'CAST('2147483699' AS int)' at row 1 |

Yes, selecting from the table is interesting, but not surprising given the warning.

(I don't have a MariaDB 10.2 instance at the moment, but testing on dbfiddle.uk indicates it too fails, though again not silently.)

MariaDB 10.3.6, default sql_mode (strict)

No warnings.

select * from g;

Gives:

+---------------------------+
| CAST('2147483699' AS int) |
+---------------------------+
|                2147483699 |
+---------------------------+
1 row in set (0.000 sec)

And the column is indeed created as bigint(10).

MySQL 8.0, both the default strict and non-strict sql_mode

ERROR 1064 (42000): 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 'int)' at line 2

Computer says no.

Conclusion

Can MariaDB or MySQL cast as bigint? As we have seen, yes, MariaDB 10.3 can (though it's not GA yet ... but surely any day now it will be). However, it can only cast as bigint implicitly. You can't explicitly cast as bigint, just like you can't cast as varchar (but see MDEV-11283), text, float, tinyint etcetera. There are only a limited number of datatypes you can cast to. This is not well documented, but CAST appears to support only the same datatypes as listed for the CONVERT function.