1. 数据库
2. 表
2.1. SELECT
SELECT 
	* 
FROM 
	SYS_USER
WHERE
	AGE > 18;
 
2.2. INSERT
INSERT INTO SYS.SYS_USER(
	ID, 
	USER_NAME, 
	AGE, 
	SEX, 
	CRT_BY, 
	CRT_TM,
	UPD_BY,
	UPD_TM
) VALUES (
	sys_guid(), 
	'ZHANGSAN', 
	18, 
	'1', 
	'100001', 
	sysdate,
	'100001',
	to_date('2024-01-01 08:00:00', 'YYYY-MM-DD HH24:MI:SS')
);
 
2.3. UPDATE
UPDATE
	SYS_USER
SET 
	USER_NAME = 'ZHANGSAN',
	AGE = 18
WHERE
	USER_ID = '0001';
 
2.4. DELETE
DELETE 
	SYS_USER
WHERE 
	USER_ID = '0001';
 
2.5. MERGE INTO
MERGE INTO 
	SYS_USER su
USING (
	<foreach collection = "list" item = "item" separator="UNION ALL">
	SELECT 
		#{req.id} AS id,
		#{req.userName} AS userName,
		#{req.age} AS age,
		#{req.sex} AS sex,
		#{req.crtBy} AS crtBy,
		#{req.crtTm} AS crtTm,
		#{req.updBy} AS updBy,
		#{req.updTm} AS updTm
	FROM dual
	</foreach>
) t
ON (
	su.id = t.id
)
WHEN MATCHED THEN 
	UPDATE SET 
		su.USER_NAME = t.userName,
		su.AGE = t.age,
		su.SEX = t.sex,
		su.UPD_BY = t.updBy,
		su.UPD_TM = t.updTm
WHEN NOT MATCHED THEN 
	INSERT (
		su.ID,
		su.USER_NAME,
		su.AGE,
		su.SEX,
		su.CRT_BY,
		su.CRT_TM,
		su.UPD_BY,
		su.UPD_TM
	) VALUES (
		sys_guid(),
		t.userName,
		t.age,
		t.sex,
		t.crtBy,
		t.crtTm,
		t.updBy,
		t.updTm
	)
 
3. 字段
3.1. 数据类型
| 数据类型 | 分类 | 简述 | 示例 | 默认 | 大小 | 
|---|---|---|---|---|---|
| NUMBER | 数字 | 精度:[1, 38]  小数位数:[-64, 127]  | NUMBER(18,4),其中18 为精度,4 为小数位数, | 精度:38  小数位数:0  | |
| BINARY_DOUBLE | 数字 | 用于存储双精度的64位浮点数 | |||
| BINARY_FLOAT | 数字 | ||||
| CHAR | 字符串 | ||||
| VARCHAR | 字符串 | ||||
| VARCHAR2 | 字符串 | ||||
| NVARCHAR2 | 字符串 | sys_guid() | |||
| LONG | 字符串 | ||||
| LONG RAW | 字符串 | ||||
| BLOB | 字符串 | ||||
| CLOB | 字符串 | ||||
| NCLOB | 字符串 | ||||
| DATE | 时间 | ||||
| TIMESTAMP | 时间 | ||||
| TIMESTAMP WITH TIME ZONE | 时间 | ||||
| TIMESTAMP WITH LOCAL TIME ZONE | 时间 | ||||
| INTERVAL_DAY_TO_SECOND | 时间 | ||||
| INTERVAL_YEAR_TO_MONTH | 时间 | ||||
| RAW | 字符串 | 
3.2. 特殊场景
| 场景 | 函数 | 示例 | 
|---|---|---|
| 主键 | sys_guid() | |
| 时间 | sysdate | TO_DATE(‘2024-01-01 08:00:00’, ‘YYYY-MM-DD HH24:MI:SS’) / TO_CHAR(SYSDATE, ‘YYYY-MM-DD HH24:MI:SS’) | 










