If f(n) = O(g(n)) and g(n) = O(h(n)) then h(n) = Ω(f(n)) 这个表述正确吗

根据引用\[2\]中的定义，如果f(n) = O(g(n))和g(n) = O(h(n))，那么意味着存在正常数c1和c2，以及n0，使得对于所有的n > n0，有0 ≤ f(n) ≤ c1 * g(n)和0 ≤ g(n) ≤ c2 * h(n)。根据这些不等式，我们可以得出结论：0 ≤ f(n) ≤ c1 * g(n) ≤ c1 * (c2 * h(n)) = (c1 * c2) * h(n)。因此，我们可以说h(n) = Ω(f(n))是正确的。
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相关问题

SET tmp_loc=INTERVAL(CONV(HEX(tmp_char),16,10),0xB0A1,0xB0C5,0xB2C1,0xB4EE,0xB6EA,0xB7A2,0xB8C1,0xB9FE,0xBBF7,0xBFA6,0xC0AC ,0xC2E8,0xC4C3,0xC5B6,0xC5BE,0xC6DA,0xC8BB,0xC8F6,0xCBFA,0xCDDA ,0xCEF4,0xD1B9,0xD4D1); IF (LENGTH(tmp_char)>1 AND tmp_loc>0 AND tmp_loc<24) THEN SELECT ELT(tmp_loc,'A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z') INTO tmp_cc; END IF; IF ASCII(tmp_cc)>64 AND ASCII(tmp_cc) <91 THEN SET tmp_rs = CONCAT(tmp_rs,tmp_cc); END IF;如何转换为postgresql的sql语句。

以下是将给定的 SQL 代码转换为 PostgreSQL 的 SQL 语句的示例：

DECLARE
    tmp_loc integer;
    tmp_cc character;
    tmp_rs character varying;
BEGIN
    tmp_loc := CONV(HEX(tmp_char), 16, 10);
    
    IF LENGTH(tmp_char) > 1 AND tmp_loc > 0 AND tmp_loc < 24 THEN
        SELECT ELT(tmp_loc, 'A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z') INTO tmp_cc; 
    END IF;
    
    IF ASCII(tmp_cc) > 64 AND ASCII(tmp_cc) < 91 THEN
        tmp_rs := CONCAT(tmp_rs, tmp_cc);
    END IF;
    
    -- 继续处理其他逻辑...
    
END;

请注意，我已将代码放在一个 PL/pgSQL 块中，并使用 `DECLARE` 声明了变量 `tmp_loc`、`tmp_cc` 和 `tmp_rs`。你可以在此基础上继续添加其他逻辑和语句。

IF LENGTH(tmp_char)>1 THEN SELECT ELT(INTERVAL(CONV(HEX(tmp_char),16,10),0xB0A1,0xB0C5,0xB2C1,0xB4EE,0xB6EA,0xB7A2,0xB8C1,0xB9FE,0xBBF7,0xBFA6,0xC0AC ,0xC2E8,0xC4C3,0xC5B6,0xC5BE,0xC6DA,0xC8BB,0xC8F6,0xCBFA,0xCDDA ,0xCEF4,0xD1B9,0xD4D1), 'A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z') INTO tmp_cc; 如何转换成postgresql的sql语句

在 PostgreSQL 中，你可以使用 `CASE` 表达式来实现类似的逻辑。下面是将给定的 SQL 代码转换为 PostgreSQL 的 SQL 语句的示例：

SELECT
    CASE
        WHEN LENGTH(tmp_char) > 1 THEN
            CASE
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 45281 AND 45285 THEN 'A'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 45457 AND 45458 THEN 'B'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 45729 AND 45755 THEN 'C'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 46062 AND 46090 THEN 'D'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 46346 AND 46378 THEN 'E'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 46498 AND 46530 THEN 'F'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 46657 AND 46689 THEN 'G'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 46817 AND 46845 THEN 'H'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 47103 AND 47127 THEN 'J'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 47334 AND 47358 THEN 'K'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 47468 AND 47492 THEN 'L'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 47610 AND 47638 THEN 'M'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 47809 AND 47829 THEN 'N'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48026 AND 48052 THEN 'O'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48162 AND 48187 THEN 'P'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48274 AND 48300 THEN 'Q'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48438 AND 48464 THEN 'R'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48657 AND 48682 THEN 'S'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 48858 AND 48883 THEN 'T'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 49189 AND 49217 THEN 'W'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 49324 AND 49354 THEN 'X'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 49382 AND 49407 THEN 'Y'
                WHEN CONV(HEX(tmp_char), 16, 10) BETWEEN 49655 AND 49690 THEN 'Z'
            END
    END AS tmp_cc;

请注意，我已经将 `ELT` 函数替换为了 `CASE` 表达式，并且使用了 `BETWEEN` 来检查给定的范围。你可能需要根据具体的需求对这些范围进行调整。