• Oracle 学习之 DML 语句


    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sysdateTO_DATE(‘2024-01-01 08:00:00’, ‘YYYY-MM-DD HH24:MI:SS’) / TO_CHAR(SYSDATE, ‘YYYY-MM-DD HH24:MI:SS’)

    4.

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  • 原文地址:https://blog.csdn.net/DreamStar2560/article/details/138974845