mysql 获得当前月1号的日期 和 0点日期方法

select timestamp(date_add(curdate(), interval - day(curdate()) + 1 day))

当月0点时间：2015-12-01 00:00:00

select timestamp(date_add(NOW(), interval - day(NOW()) + 1 day))

当月1号时间：2015-12-01 10:45:22

select date_add(curdate(), interval - day(curdate()) + 1 day)

2015-12-01

<!-- 查询上月债权额度 -->
    <select id="getLastMonthSubCreditAmount" parameterType="int" resultType="java.math.BigDecimal">
        <![CDATA[SELECT COUNT(si.subCreditAmount) FROM subcredit_info si
        INNER JOIN order_info oi ON si.subCreditId = oi.subCreditId
        WHERE
        si.`addTime` < TIMESTAMP (
        date_add(
            curdate(),
            INTERVAL - DAY (curdate()) + 1 DAY
            )
        )
        AND oi.`status` > 5
        AND year(si.interestEndDate)<=year(now())
        AND month(si.interestEndDate)<(month(now())-1)
        AND si.companyId = #{companyId}    ]]>
    </select>