1.SELECT * FROM ....
WHERE NAME IN ( 'NAME1 ')
2.SELECT * FROM ....
WHERE AGET= 3
3.SELECT * FROM ....
WHERE NAME IN ( 'NAME1 ') AND AGET= 3
1和2的效率差不多多.但3却需要1的40倍时间来查询,为什么会这样????
真实语句如下:
SELECT dbo.USER_INFO.USER_NAME, dbo.SCR_FORM.SCR_FORM_ID, dbo.SCR_FORM.SCR_FORM_CODE, dbo.SCR_FORM.PRJ_CONTRACT_CD,
dbo.SCR_FORM.SC_TYPE, dbo.SCR_FORM.SC_FRAME, dbo.SCR_FORM.OS_VENDOR_CODE, dbo.SCR_FORM.OS_TEAM_CODE,
dbo.SCR_FORM.SUBMIT_DATE, dbo.SCR_FORM.STATUS, dbo.SCR_FORM.SUBMITTER_USER_CD, dbo.SCR_FORM.BGM_USER_CD,
dbo.SCR_FORM.CPM_USER_CD, dbo.SCR_FORM.CPD_USER_CD, dbo.SCR_FORM.OS_USER_CD, dbo.OS_VENDOR.FULL_NAME AS VENDORNAME,
dbo.OS_TEAM.FULL_NAME AS TEAMNAME, dbo.PROJECT.PROJECT_NAME, dbo.PROJECT.PARTY_ID
FROM dbo.SCR_FORM INNER JOIN
dbo.PROJECT ON dbo.SCR_FORM.PRJ_CONTRACT_CD = dbo.PROJECT.PROJECT_CD LEFT OUTER JOIN
dbo.USER_INFO ON dbo.SCR_FORM.SUBMITTER_USER_CD = dbo.USER_INFO.USER_CD LEFT OUTER JOIN
dbo.OS_TEAM ON dbo.SCR_FORM.OS_TEAM_CODE = dbo.OS_TEAM.OS_TEAM_CODE LEFT OUTER JOIN
dbo.OS_VENDOR ON dbo.SCR_FORM.OS_VENDOR_CODE = dbo.OS_VENDOR.OS_VENDOR_CODE
--下面是in条件
where SCR_FORM.SCR_FORM_CODE in
(SELECT
distinct SC_ITEM.SCR_FORM_CODE
FROM dbo.SC_ITEM
INNER JOIN
dbo.EI_ORDER_ITEM on EI_ORDER_ITEM.TASK_ID =SC_ITEM.task_id INNER JOIN
dbo.PRODUCT_LINE ON dbo.EI_ORDER_ITEM.PRODUCT_LINE = dbo.PRODUCT_LINE.PRODUCT_LINE_CD