目录

• 查找最大数
• 查找总数和数量
• IF语句
• 根据指定年月查询

查找最大数

 select max(t.sort_order) from content t

查找总数和数量

 <select id="##" parameterType="map" resultType="map">
        SELECT    
            (SELECT SUM(AMOUNT) FROM PAY T WHERE T.CARD_ID IN (SELECT B.ID FROM CARD B WHERE B.ID = #{id} ) ) amount,
            (SELECT COUNT(1) FROM PAY T WHERE T.CARD_ID IN (SELECT B.ID FROM CARD B WHERE B.ID = #{id} ) ) payTimes
        FROM DUAL
  </select>

IF语句

 <select id="##" parameterType="map" resultType="java.lang.Integer">
        SELECT COUNT(1) FROM ** T
        LEFT JOIN USER M
        ON T.ID = M.ID
         WHERE 1 = 1
        <if test="type != null and type != ''">
            AND T.TYPE = #{type ,jdbcType=VARCHAR}
        </if>
    </select>

根据指定年月查询

    <select id="##" resultType="java.lang.Double" parameterType="map" >
    SELECT COUNT(*) amount FROM **C
    LEFT JOIN USER M ON C.ID = M.ID  WHERE 1 = 1
    <if test="year!= null and year > 0 and (month == null or month == 0)">
        AND TO_NUMBER(TO_CHAR(C.CREATION_TIME 'YYYY')) = #{year ,jdbcType=DECIMAL}
    </if>
    <if test="year!= null and year > 0 and month != null and month > 0">
        AND TO_NUMBER(TO_CHAR(C.CREATION_TIME, 'YYYY')) = #{year ,jdbcType=DECIMAL}
        AND TO_NUMBER(TO_CHAR(C.CREATION_TIME, 'MM')) = #{month ,jdbcType=DECIMAL}
    </if>
    </select>