我正在使用此代碼從我創建的表中檢索數據。SELECT語句不能正常工作
SELECT id,shirt_name,boys FROM shirts WHERE boys IS NOT NULL
而不是隻選擇boys列中輸入的行,它會選擇所有行。這是我創建表格的方式
CREATE TABLE shirts (
id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY NOT NULL,
shirt_name VARCHAR(20) NOT NULL,
men VARCHAR(10) NULL,
women VARCHAR(10) NULL,
boys VARCHAR(10) NULL,
girls VARCHAR(10) NULL,
babies VARCHAR(10) NULL,
)ENGINE=INNODB;
INSERT INTO shirts(shirt_name,men,women,boys,girls,babies) VALUES
('Crewneck Tee','me_crn','wo_crn','bo_crn','gi_crn','ba_crn'),
('V-Neck Tee','me_vnc','wo_vnc','','',''),
('Scoop Neck Tee','','wo_sco','','',''),
('Raglan Tee','me_rag','wo_rag','bo_rag','gi_rag',''),
('Ringer Tee','me_rin','wo_rin','bo_rin','gi_rin',''),
('Cap Sleeve Tee','','wo_cap','','gi_cap',''),
('Tank Top','me_tan','wo_tan','bo_tan','gi_tan',''),
('Spaghetti Strap','','wo_spa','','',''),
('Hoodie','me_hod','wo_hod','bo_hod','gi_hod','ba_hod');
我做錯了什麼?
非空字符串(即空格)列使用什麼? –