SQL - 用于过滤查询的CASE语句

Question

大家好，我正在选择相同列的存储过程，我的查询如下

CREATE PROCEDURE GET_DATA
    @in_filter_column1 NVARCHAR(6),
    @in_filter_column2 NVARCHAR(50),
    @in_flag BIT = 0
AS
BEGIN
    IF @in_flag = 0
        SELECT      t1.COLUMN1, t1.COLUM2, t2.COLUMN3
        FROM        table1 t1
        INNER JOIN  table2 t2
        ON          t1.column1 = t2.column1
        WHERE       t1.column1 = @in_filter_column1
    ELSE
        SELECT      t1.COLUMN1, t1.COLUM2, t2.COLUMN3
        FROM        table1 t1
        INNER JOIN  table2 t2
        ON          t1.column1 = t2.column1
        INNER JOIN  table3 t3
        ON          t3.column1 = t2.column1
        WHERE       t3.column1 = @in_filter_column2
END

所以这里不是写相同的选择条件我想简单地使用开关盒或其他替代方式。是否可能

我知道的一种方式就是这样我正在尝试其他任何方式

CREATE PROCEDURE GET_DATA
        @in_filter_column1 NVARCHAR(6),
        @in_filter_column2 NVARCHAR(50),
        @in_flag BIT = 0
    AS
    BEGIN
    DECLARE @sql_query NVARCHAR(MAX)
    SET @sql_query = ' SELECT       t1.COLUMN1, t1.COLUM2, t2.COLUMN3
            FROM        table1 t1
            INNER JOIN  table2 t2
            ON          t1.column1 = t2.column1'

        IF @in_flag = 0
        SET @sql_query = @sql_query + ' WHERE t1.column1 = ''' + @in_filter_column1 +''''
        ELSE
            SET @sql_query = @sql_query + ' INNER JOIN  table2 t3
                            ON      t3.column1 = t1.column1 WHERE t3.column1 = ''' + @in_filter_column2 +''''
        END