我正在寻找一种生成字母序列的方法：
AA, AB, AC, AD, AE, ..., ZZ。
任何人都可以在oracle中建议一种方便的方法。
答案 0 :(得分：3)
如果你想在纯SQL中完成它，这似乎有用：
SELECT CHR(divided+65)||CHR(remainder+65)
FROM (
SELECT 0 AS initial_val,
0 AS divided,
0 AS remainder
FROM dual
UNION
SELECT LEVEL AS initial_val,
TRUNC(LEVEL/26) AS divided,
MOD(LEVEL,26) AS remainder
FROM dual
CONNECT BY LEVEL <= 675)
ORDER BY initial_val
它构建了一个包含676行的列表（必须使用union作为分层查询中的第一条记录从1开始而不是0）。
676是26 x 26，因此它将数字除以得到前导字母的数字（转换为主SELECT中的字母）并使用该部分的剩余部分作为尾随字母。
然后我添加65以将数字输入到ascii区域以获得字母，然后就可以了。
希望它有所帮助;
答案 1 :(得分：2)
使用SQL MODEL子句生成行列表：
SELECT s
FROM (select chr(level + 65 - 1) pos1 from dual connect by level <= 26)
MODEL
DIMENSION BY (pos1 AS x, 'A' as y)
MEASURES ('--' AS s)
RULES UPSERT ALL ITERATE (26)
(
s[any, chr(iteration_number + 65)] = (CV(x) || CV(y))
)
ORDER BY s;
示例运行：
09/12/2015 19:55:26:SQL> SELECT s
2 FROM (select chr(level + 65 - 1) pos1 from dual connect by level <= 26)
3 MODEL
4 DIMENSION BY (pos1 AS x, 'A' as y)
5 MEASURES ('--' AS s)
6 RULES UPSERT ALL ITERATE (26)
7 (
8 s[any, chr(iteration_number + 65)] = (CV(x) || CV(y))
9 )
10 ORDER BY s;
S
--
AA
AB
AC
AD
AE
etc ...
然后我们可以使用LISTAGG运行简单聚合，如下所示：
WITH t AS (
SELECT s
FROM (select chr(level + 65 - 1) pos1 from dual connect by level <= 26)
MODEL
DIMENSION BY (pos1 AS x, 'A' as y)
MEASURES ('--' AS s)
RULES UPSERT ALL ITERATE (26)
(
s[any, chr(iteration_number + 65)] = (CV(x) || CV(y))
)
ORDER BY s)
-- data generated, now aggregate
SELECT listagg(s, ', ') WITHIN GROUP (ORDER BY s) aggreg_list
FROM t;
结果：
09/12/2015 19:52:59:SQL> WITH t AS (
2 SELECT s
3 FROM (select chr(level + 65 - 1) pos1 from dual connect by level <= 26)
4 MODEL
5 DIMENSION BY (pos1 AS x, 'A' as y)
6 MEASURES ('--' AS s)
7 RULES UPSERT ALL ITERATE (26)
8 (
9 s[any, chr(iteration_number + 65)] = (CV(x) || CV(y))
10 )
11 ORDER BY s)
12 -- data generated, now aggregate
13 SELECT listagg(s, ', ') WITHIN GROUP (ORDER BY s) aggreg_list
14 FROM t;
AGGREG_LIST
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
AA, AB, AC, AD, AE, AF, AG, AH, AI, AJ, AK, AL, AM, AN, AO, AP, AQ, AR, AS, AT, AU, AV, AW, AX, AY, AZ, BA, BB, BC, BD, BE, BF, BG, BH, BI, BJ, BK, BL, BM, BN, BO, BP, BQ, BR, BS, BT, BU, BV, BW, BX, BY, BZ, CA, CB, CC, CD, CE, CF, CG, CH, CI, CJ, CK, CL, CM, CN, CO, CP, CQ, CR, CS, CT, CU, CV, CW, CX, CY, CZ, DA, DB, DC, DD, DE, DF, DG, DH, DI, DJ, DK, DL, DM, DN, DO, DP, DQ, DR, DS, DT, DU, DV, DW, DX, DY, DZ, EA, EB, EC, ED, EE, EF, EG, EH, EI, EJ, EK, EL, EM, EN, EO, EP, EQ, ER, ES, ET, EU,
EV, EW, EX, EY, EZ, FA, FB, FC, FD, FE, FF, FG, FH, FI, FJ, FK, FL, FM, FN, FO, FP, FQ, FR, FS, FT, FU, FV, FW, FX, FY, FZ, GA, GB, GC, GD, GE, GF, GG, GH, GI, GJ, GK, GL, GM, GN, GO, GP, GQ, GR, GS, GT, GU, GV, GW, GX, GY, GZ, HA, HB, HC, HD, HE, HF, HG, HH, HI, HJ, HK, HL, HM, HN, HO, HP, HQ, HR, HS, HT, HU, HV, HW, HX, HY, HZ, IA, IB, IC, ID, IE, IF, IG, IH, II, IJ, IK, IL, IM, IN, IO, IP, IQ, IR, IS, IT, IU, IV, IW, IX, IY, IZ, JA, JB, JC, JD, JE, JF, JG, JH, JI, JJ, JK, JL, JM, JN, JO, JP,
JQ, JR, JS, JT, JU, JV, JW, JX, JY, JZ, KA, KB, KC, KD, KE, KF, KG, KH, KI, KJ, KK, KL, KM, KN, KO, KP, KQ, KR, KS, KT, KU, KV, KW, KX, KY, KZ, LA, LB, LC, LD, LE, LF, LG, LH, LI, LJ, LK, LL, LM, LN, LO, LP, LQ, LR, LS, LT, LU, LV, LW, LX, LY, LZ, MA, MB, MC, MD, ME, MF, MG, MH, MI, MJ, MK, ML, MM, MN, MO, MP, MQ, MR, MS, MT, MU, MV, MW, MX, MY, MZ, NA, NB, NC, ND, NE, NF, NG, NH, NI, NJ, NK, NL, NM, NN, NO, NP, NQ, NR, NS, NT, NU, NV, NW, NX, NY, NZ, OA, OB, OC, OD, OE, OF, OG, OH, OI, OJ, OK,
OL, OM, ON, OO, OP, OQ, OR, OS, OT, OU, OV, OW, OX, OY, OZ, PA, PB, PC, PD, PE, PF, PG, PH, PI, PJ, PK, PL, PM, PN, PO, PP, PQ, PR, PS, PT, PU, PV, PW, PX, PY, PZ, QA, QB, QC, QD, QE, QF, QG, QH, QI, QJ, QK, QL, QM, QN, QO, QP, QQ, QR, QS, QT, QU, QV, QW, QX, QY, QZ, RA, RB, RC, RD, RE, RF, RG, RH, RI, RJ, RK, RL, RM, RN, RO, RP, RQ, RR, RS, RT, RU, RV, RW, RX, RY, RZ, SA, SB, SC, SD, SE, SF, SG, SH, SI, SJ, SK, SL, SM, SN, SO, SP, SQ, SR, SS, ST, SU, SV, SW, SX, SY, SZ, TA, TB, TC, TD, TE, TF,
TG, TH, TI, TJ, TK, TL, TM, TN, TO, TP, TQ, TR, TS, TT, TU, TV, TW, TX, TY, TZ, UA, UB, UC, UD, UE, UF, UG, UH, UI, UJ, UK, UL, UM, UN, UO, UP, UQ, UR, US, UT, UU, UV, UW, UX, UY, UZ, VA, VB, VC, VD, VE, VF, VG, VH, VI, VJ, VK, VL, VM, VN, VO, VP, VQ, VR, VS, VT, VU, VV, VW, VX, VY, VZ, WA, WB, WC, WD, WE, WF, WG, WH, WI, WJ, WK, WL, WM, WN, WO, WP, WQ, WR, WS, WT, WU, WV, WW, WX, WY, WZ, XA, XB, XC, XD, XE, XF, XG, XH, XI, XJ, XK, XL, XM, XN, XO, XP, XQ, XR, XS, XT, XU, XV, XW, XX, XY, XZ, YA,
YB, YC, YD, YE, YF, YG, YH, YI, YJ, YK, YL, YM, YN, YO, YP, YQ, YR, YS, YT, YU, YV, YW, YX, YY, YZ, ZA, ZB, ZC, ZD, ZE, ZF, ZG, ZH, ZI, ZJ, ZK, ZL, ZM, ZN, ZO, ZP, ZQ, ZR, ZS, ZT, ZU, ZV, ZW, ZX, ZY, ZZ
答案 2 :(得分：1)
使用这个，你可以生成任何长度的序列：
SQL> with input as (
2 select 0 as start_position, 3 as strings_length, 35 as sequence_elements, ascii('Z')-ascii('A')+1 as base, ascii('A') as start_val
3 from dual
4 )
5 select sequence_position, listagg(character,'') within group(order by char_level desc) as sequence_value
6 from (
7 select inp_sequence.*, format.*, chr(start_val + mod(trunc(sequence_position / power(base, char_level)),base)) as character
8 from (
9 select i.*, start_position + rownum-1 as sequence_position
10 from input i
11 connect by rownum <= sequence_elements
12 ) inp_sequence
13 cross join (
14 select rownum-1 as char_level
15 from input
16 connect by rownum <= strings_length
17 ) format
18 )
19 group by sequence_position
20 /
SEQUENCE_POSITION SEQUENCE_VALUE
----------------- --------------------------------------------------------------------------------
0 AAA
1 AAB
2 AAC
3 AAD
4 AAE
5 AAF
6 AAG
7 AAH
8 AAI
9 AAJ
10 AAK
11 AAL
12 AAM
13 AAN
14 AAO
15 AAP
16 AAQ
17 AAR
18 AAS
19 AAT
20 AAU
21 AAV
22 AAW
23 AAX
24 AAY
25 AAZ
26 ABA
27 ABB
28 ABC
29 ABD
30 ABE
31 ABF
32 ABG
33 ABH
34 ABI
35 rows selected
SQL>
下面：