迪丽热巴亲吻图片大全:关于select count()

来源:百度文库 编辑:高考问答 时间:2024/05/11 15:19:57
1、首先想知道select count(*) from 的from后面是不是只可以跟一个表名?

2、下面的语句是从两个表中检索的SQL文,请问如何取得其检索结果的条数,也就是用select count(*)该怎么写?望高手指点!

SELECT
STM_MITSUMORI_JOKEN_PATTERN.MITSUMORI_JOKEN_PAT_NO
,STM_MITSUMORI_JOKEN_PATTERN.MITSUMORI_JOKEN_PAT_NM
,STM_MITSUMORI_JOKEN_PATTERN.BIKO
,STM_TORIHIKISAKI.TORIHIKISAKI_CODE
,STM_TORIHIKISAKI.TORIHIKISAKI_NM

FROM
STM_MITSUMORI_JOKEN_PATTERN A
,STM_TORIHIKISAKI B

WHERE
STM_MITSUMORI_JOKEN_PATTERN.RIYO_KIGYO_CODE=#riyo_Kigyo_Code#
<isNotEmpty property="mitsumori_Joken_Pat_No_From">
AND A.MITSUMORI_JOKEN_PAT_NO >= #mitsumori_Joken_Pat_No_From#
</isNotEmpty>
<isNotEmpty property="mitsumori_Joken_Pat_No_To">
AND A.MITSUMORI_JOKEN_PAT_NO <= #mitsumori_Joken_Pat_No_To#
</isNotEmpty>
<isNotEmpty property="mitsumori_Joken_Pat_Nm">
AND A.MITSUMORI_JOKEN_PAT_NM like #mitsumori_Joken_Pat_Nm# || '%'
</isNotEmpty>
<isNotEmpty property="tokuisaki_Code">
AND A.TOKUISAKI_CODE=#tokuisaki_Code#
</isNotEmpty>
AND B.RIYO_KIGYO_CODE (+)= A.RIYO_KIGYO_CODE
AND B.TORIHIKISAKI_CODE (+)= A.TOKUISAKI_CODE

<dynamic prepend="order by">
<isEqual prepend="," property="narabekae1" compareValue="1">
B.HANSHA_KBN
</isEqual>
<isEqual prepend="," property="narabekae1" compareValue="2">
B.HANSHA_KBN DESC
</isEqual>
<isEqual prepend="," property="narabekae1" compareValue="3">
A.MITSUMORI_JOKEN_PAT_NO
</isEqual>
<isEqual prepend="," property="narabekae1" compareValue="4">
A.MITSUMORI_JOKEN_PAT_NO DESC
</isEqual>
<isEqual prepend="," property="narabekae1" compareValue="5">
A.TOKUISAKI_CODE
</isEqual>
<isEqual prepend="," property="narabekae1" compareValue="6">
A.TOKUISAKI_CODE desc
</isEqual>
,<isEqual prepend="," property="narabekae2" compareValue="1">
B.HANSHA_KBN
</isEqual>
<isEqual prepend="," property="narabekae2" compareValue="2">
B.HANSHA_KBN DESC
</isEqual>
<isEqual prepend="," property="narabekae2" compareValue="3">
A.MITSUMORI_JOKEN_PAT_NO
</isEqual>
<isEqual prepend="," property="narabekae2" compareValue="4">
A.MITSUMORI_JOKEN_PAT_NO DESC
</isEqual>
<isEqual prepend="," property="narabekae2" compareValue="5">
A.TOKUISAKI_CODE
</isEqual>
<isEqual prepend="," property="narabekae2" compareValue="6">
A.TOKUISAKI_CODE desc
</isEqual>
</dynamic>

多谢了!!!

可以跟多个表名,但要用join连接起来,如
select count(*) from ta full join tb on ta.id=tb.id

select count(*) from 的from后面可以只跟一个表名
它统计的是结果集中至少包含一个非NULL值的行数
就是统计不全是NULL值的行数