Question

我正在尝试进行以下操作的查询：

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我在if子句中的If条件中唯一可以找到的是CASES。我无法找到允许多个条件的案例。

到目前为止，我必须通过在SELECT语句之外使用If并复制语句但更改WHERE子句来实现此目的。

Answer 1

SELECT * FROM Test
WHERE
(Condition = True
    AND Column1 = 'This'
    AND Column2 = 'That')
OR
(Condition = FALSE
    AND Column3 = 'This'
    AND column4 = 'That')

Answer 2

您可以使用PROCEDURE或FUNCTION来执行此操作。

例如使用PROCEDURE：

CREATE PROCEDURE test (IN _condition BOOLEAN, IN _this VARCHAR(255), IN _that VARCHAR(255))
BEGIN
    IF _condition THEN
        SELECT * FROM Test WHERE Column1 = _this AND Column2 = _that;
    ELSE
        SELECT * FROM Test WHERE Column3 = _this AND Column4 = _that;
    END IF;
END;

要运行此功能，请执行CALL test(TRUE, 'This', 'That')

您可以将 _ condition 替换为您自己的条件，例如：

CREATE PROCEDURE test1 (IN _number INT(11), IN _this VARCHAR(255), IN _that VARCHAR(255))
BEGIN
    IF _number >= 2016 THEN
        SELECT * FROM Test WHERE Column1 = _this AND Column2 = _that;
    ELSE
        SELECT * FROM Test WHERE Column3 = _this AND Column4 = _that;
    END IF;
END;

执行CALL test1(2015, 'This', 'That')

带有IF的MSSQL WHERE

2 个答案: