我正在寻找一种生成字母序列的方法：
AA, AB, AC, AD, AE, ..., ZZ任何人都可以建议在 oracle 中执行此操作的便捷方法吗？
如果你想用纯 SQL 完成它，这似乎可行：
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，因为分层查询中的第一条记录从 1 而不是 0 开始）。
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然后我添加 65 将数字放入字母表字母的 ASCII 区域中，然后就可以了。
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 运行简单的聚合，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
用这个你可以生成任意长度的序列：
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>
这里：