[20231207]開發不應該這樣寫sql4.txt

--//最近在最佳化sql語句，發現另外一種風格，實際上以前也遇到過，感覺這就像一種病，會傳染只要一個這樣寫後面的要麼跟進要麼
--//不改。我覺得開發應該感謝exadata，不然我們的生產系統估計會垮掉。

1.環境：
XXXXXX> @ver1
PORT_STRING                    VERSION        BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

2.問題語句：
XXXXXX> @ sql_id ag76s7zum6z3b

--SQL_ID = ag76s7zum6z3b

SELECT MZ.BRID AS PATIENT_ID,
       TO_CHAR(GH.SBXH) AS OUTPATIENT_ID,
       :"SYS_B_0" AS INHOSPITAL_ID, JZLS.JZXH AS VISIT_ID, MZ.MZHM AS CARD_NO,
       GH.GHSJ AS VISIT_TIME, MZ.BRXM AS PATIENT_NAME, MZ.BRXB AS PATIENT_SEX,
       MZ.CSNY AS PATIENT_BIRTHDATE, MZ.SFZH AS IDENTITY_CARD_ID,
       :"SYS_B_1" AS PATIENT_TYPE,
       (SELECT GY_DMZD.DMMC FROM XXXXXX_YYY.GY_DMZD WHERE GY_DMZD.DMLB    = :"SYS_B_2" AND GY_DMZD.DMSB = MZ.MZDM) AS PATIENT_NATION,
       (SELECT GY_SSXWH.NAME FROM XXXXXX_YYY.GY_SSXWH WHERE GY_SSXWH.SBXH = MZ.XZZ_SQS) AS FAMILY_ADDRESS_PROVINCE,
       (SELECT GY_SSXWH.NAME FROM XXXXXX_YYY.GY_SSXWH WHERE GY_SSXWH.SBXH = MZ.XZZ_S) AS FAMILY_ADDRESS_CITY,
       MZ.LXDZ AS FAMILY_ADDRESS_DETAIL, MZ.LXDH AS MOBILE_PHONE,
       GY.KSDM AS DEPART_CODE, GY.KSMC AS DEPART_NAME,
       KS.KSDM AS SUB_DEPART_CODE, KS.KSMC AS SUB_DEPART_NAME,
       (SELECT CSZ FROM GY_XTCS WHERE CSMC                                = :"SYS_B_3") AS HOS_ID
FROM XXXXXX_YYY.MS_BRDA MZ
LEFT JOIN XXXXXX_YYY.MS_GHMX GH
    ON MZ.BRID = GH.BRID
LEFT JOIN XXXXXX_YYY.MS_GHKS KS
    ON GH.KSDM = KS.KSDM
LEFT JOIN XXXXXX_YYY.GY_KSDM GY
    ON KS.MZKS = GY.KSDM
LEFT JOIN XXXXXX_YYY.YS_MZ_JZLS JZLS
    ON JZLS.GHXH = GH.SBXH
WHERE ((:card_no = :"SYS_B_4" OR :card_no IS NULL) OR MZ.MZHM = :card_no)
   AND ((:patient_id = :"SYS_B_5" OR :patient_id IS NULL) OR MZ.BRID = :patient_id)
   AND ((:patientName = :"SYS_B_6" OR :patientName IS NULL) OR MZ.BRXM = :patientName)
   AND ((:patientSex = :"SYS_B_7" OR :patientSex IS NULL) OR MZ.BRXB = :patientSex)
   AND ((:deptName = :"SYS_B_8" OR :deptName IS NULL) OR GY.KSMC = :deptName);
--//我做了格式化處理，原始程式程式碼就一行。
--//可以看出開發的本意，就是帶入任意引數都可以查詢。可惜oracle 最佳化器沒有這麼智慧，無法選擇合理的執行路徑。
--//根據輸入選擇合適的索引,導致選擇全部掃描。

SYS@192.168.100.141:1621/dbcn/dbcn1> @ seg2 %.MS_BRDA
    SEG_MB OWNER                SEGMENT_NAME                   SEGMENT_TYPE         SEG_TABLESPACE_NAME                BLOCKS     HDRFIL     HDRBLK
---------- -------------------- ------------------------------ -------------------- ------------------------------ ---------- ---------- ----------
      1656 XXXXXX_YYY           MS_BRDA                        TABLE                XXXXXX_YYY                         211968         52     852001
--//1.6G.

--//執行計劃如下:
Plan hash value: 1015797529
----------------------------------------------------------------------------------------------------------------------------------
| Id | Operation                        | Name              | E-Rows |E-Bytes| Cost (%CPU)| E-Time   | OMem | 1Mem | Used-Mem |
----------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                 |                   |        |       | 60543 (100)|          |       |       |          |
|   1 | TABLE ACCESS BY INDEX ROWID     | GY_DMZD           |      1 |    20 |     2   (0)| 00:00:01 |       |       |          |
|* 2 |   INDEX UNIQUE SCAN              | PK_GY_DMZD        |      1 |       |     1   (0)| 00:00:01 | 1025K| 1025K|          |
|   3 | TABLE ACCESS BY INDEX ROWID     | GY_SSXWH          |      1 |    13 |     2   (0)| 00:00:01 |       |       |          |
|* 4 |   INDEX UNIQUE SCAN              | PK_GY_SSXWH       |      1 |       |     1   (0)| 00:00:01 | 1025K| 1025K|          |
|   5 | TABLE ACCESS BY INDEX ROWID     | GY_SSXWH          |      1 |    13 |     2   (0)| 00:00:01 |       |       |          |
|* 6 |   INDEX UNIQUE SCAN              | PK_GY_SSXWH       |      1 |       |     1   (0)| 00:00:01 | 1025K| 1025K|          |
|   7 | TABLE ACCESS BY INDEX ROWID     | GY_XTCS           |      1 |    18 |     2   (0)| 00:00:01 |       |       |          |
|* 8 |   INDEX UNIQUE SCAN              | PK_GY_XTCS        |      1 |       |     1   (0)| 00:00:01 | 1025K| 1025K|          |
|   9 | NESTED LOOPS OUTER              |                   |    805 |   123K| 60543   (1)| 00:12:07 |       |       |          |
|* 10 |   FILTER                         |                   |        |       |            |          |       |       |          |
|* 11 |    HASH JOIN RIGHT OUTER         |                   |    687 | 99615 | 58034   (1)| 00:11:37 | 2782K| 2782K| 1588K (0)|
| 12 |     TABLE ACCESS STORAGE FULL    | GY_KSDM           |   1099 | 24178 |     7   (0)| 00:00:01 | 1025K| 1025K|          |
|* 13 |     HASH JOIN RIGHT OUTER        |                   |    687 | 84501 | 58027   (1)| 00:11:37 | 2596K| 2596K| 1573K (0)|
| 14 |      TABLE ACCESS STORAGE FULL   | MS_GHKS           |    429 | 11583 |     5   (0)| 00:00:01 | 1025K| 1025K|          |
| 15 |      NESTED LOOPS OUTER          |                   |    687 | 65952 | 58022   (1)| 00:11:37 |       |       |          |
|* 16 |       TABLE ACCESS STORAGE FULL | MS_BRDA           |     92 | 6532 | 57498   (1)| 00:11:30 | 1025K| 1025K|          |
| 17 |       TABLE ACCESS BY INDEX ROWID| MS_GHMX           |      8 |   200 |    10   (0)| 00:00:01 |       |       |          |
|* 18 |        INDEX RANGE SCAN          | IDX_MS_GHMX_BRID |      8 |       |     2   (0)| 00:00:01 | 1025K| 1025K|          |
| 19 |   TABLE ACCESS BY INDEX ROWID    | YS_MZ_JZLS        |      1 |    12 |     4   (0)| 00:00:01 |       |       |          |
|* 20 |    INDEX RANGE SCAN              | I_YS_MZ_JZLS_GHXH |      1 |       |     2   (0)| 00:00:01 | 1025K| 1025K|          |
----------------------------------------------------------------------------------------------------------------------------------

SYS@192.168.100.141:1621/dbcn/dbcn1> @ bind_cap ag76s7zum6z3b :card_no
SQL_ID        CHILD_NUMBER WAS NAME      POSITION MAX_LENGTH LAST_CAPTURED       DATATYPE_STRING VALUE_STRING
------------- ------------ --- --------- -------- ---------- ------------------- --------------- ------------
ag76s7zum6z3b            0 YES :CARD_NO         5         32 2023-12-06 09:54:09 VARCHAR2(32)    90377195
                         1 YES :CARD_NO         5         32 2023-12-05 11:29:35 VARCHAR2(32)    02666713
                         2 YES :CARD_NO         5         32 2023-12-06 19:33:57 VARCHAR2(32)    91544379

SYS@192.168.100.141:1621/dbcn/dbcn1> @ bind_cap_awr ag76s7zum6z3b ''
no rows selected

--//這樣語句在awr歷史表還沒有記錄。可以發現在共享池抓到的sql語句都是帶入card_no引數的。
--//我多次提過不要這樣寫sql語句，這不是在學校寫家庭作業,這是生產系統!!這類語句在生產系統還有一大堆，真不知道現在的畢業生
--//如何畢業的。

[20231207]開發不應該這樣寫sql4.txt

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