更新时间:2023-11-04 GMT+08:00
条件语句
语法
IF <condition1> THEN
<perform action1>
[ELSIF <condition2> THEN
<perform action2>
]
…
[ELSIF <conditionN> THEN
<perform actionN>
]
…
[ELSE
<perform default action>
]
END IF;
示例
根据上述语法结构,IF存在以下几种表现形式:
- IF-THEN,例如:
IF v_user_id <> 0 THEN SELECT col1 INTO a FROM users WHERE user_id = v_user_id; END IF;
- IF-THEN-ELSE,例如:
IF parentid IS NULL OR parentid = '' THEN RETURN; ELSE SELECT col1 INTO a FROM users WHERE user_id = v_user_id; END IF;
- IF-THEN-ELSE IF,例如:
IF sex = 'm' THEN pretty_sex := 'man'; ELSE IF sex = 'f' THEN pretty_sex := 'woman'; END IF; END IF;
- IF-THEN-ELSIF-ELSE,例如:
IF number = 0 THEN result := 'zero'; ELSIF number > 0 THEN result := 'positive'; ELSE result := 'negative'; END IF;
父主题: 控制结构