有没有办法在通配符选择的所有列上测试null？

Question

伪：

select * from foo where [every column is not null] 

有没有办法做到这一点，而无需指定的实际列名称？

Answer 1

，我能想到的一种可能的解决方案包括使用动态-SQL

SELECT GROUP_CONCAT(column_name SEPARATOR ' IS NOT NULL AND ') 
    INTO @sql 
    FROM INFORMATION_SCHEMA.COLUMNS 
WHERE table_schema = SCHEMA() 
    AND table_name = 'foo' 
GROUP BY table_name; 

SET @sql = CONCAT('SELECT * FROM foo WHERE ', @sql, ' IS NOT NULL'); 

PREPARE stmt FROM @sql; 
EXECUTE stmt; 
DEALLOCATE PREPARE stmt; 

在这里被SQLFiddle演示

---

显然它可以被包装成带有参数的存储过程表名

DELIMITER $$ 
CREATE PROCEDURE sp_select_all_not_null(IN tbl_name VARCHAR(64)) 
BEGIN 
    SELECT GROUP_CONCAT(column_name SEPARATOR ' IS NOT NULL AND ') 
    INTO @sql 
    FROM INFORMATION_SCHEMA.COLUMNS 
    WHERE table_schema = SCHEMA() 
    AND table_name = tbl_name 
    GROUP BY table_name; 

    SET @sql = CONCAT('SELECT * FROM ', tbl_name, ' WHERE ', @sql, ' IS NOT NULL'); 

    PREPARE stmt FROM @sql; 
    EXECUTE stmt; 
    DEALLOCATE PREPARE stmt; 
END 
DELIMITER ; 

，然后用它

CALL sp_select_all_not_null('foo'); 

这里是SQLFiddle演示为