A. 求問一個sql語句
SELECT A.ID,A.PRJNAME,nvl(B1.CID,0) MCount,nvl(B2.CID,0) Count
FROM A,
(select BB.id ID,count(BB.id) CID, BB.TIME
from (SELECT ID,substrb(to_char(time,'YYYYMMDD'),1,6) TIME FROM B) BB
--where time='YYYYMM' 可在此添加月份篩選
GROUP by BB.id,BB.time
ORDER BY BB.ID)B1,--每月到位次數
(SELECT ID,COUNT(ID) CID FROM B GROUP BY ID)B2--總共到位次數
WHERE A.ID=B1.ID(+) AND
A.ID=B2.ID(+);
註：這是在oracle里寫的 函數需要換下 不過思路應該沒問題
B. 關於復雜的SQL查詢
SELECT distinct(CASE
WHEN 列 = 'XY-P-01' THEN
列
WHEN substrb(列,1,6)='XY-P-0' THEN
'XY-P-0'
WHEN substrb(列,1,6)='XY-P-1' THEN
'XY-P-1'
ELSE
'YZ-S-0'
END)
FROM 表;
C. oracle資料庫SQL取月份問題
假如你說的列為col，表名為table，欄位為日期型，做法如下：
SELECT col
FROM table
WHERE substr(to_char(col,'yyyymmdd'),1,6) = '200704'
D. 將數據進行sql分組統計 部門 狀態 1 X 2 A 1 A 2 T 1 T 統計成 部門 狀態X 狀態A 狀態T 1 1 1 1 2 0 1 1
除非狀態是有限的幾個可以這樣完成。無論怎麼轉列，列的名稱必須是明確的。如果不固定就只能考慮動態SQL，那麼就只有靠寫存儲過程。
狀態固定情況下的例子：
SELECT id,
MAX(decode(cn, 'c1', cv, NULL)) AS c1,
MAX(decode(cn, 'c2', cv, NULL)) AS c2,
MAX(decode(cn, 'c3', cv, NULL)) AS c3
FROM t_row_col
GROUP BY id
ORDER BY 1;
不固定情況下的存儲過程參考
包中
p_rows_column_real用於前述的第一種不限定列的轉換；
p_rows_column用於前述的第二種不限定列的轉換。
CREATE OR REPLACE PACKAGE pkg_dynamic_rows_column AS
TYPE refc IS REF CURSOR;
PROCEDURE p_print_sql(p_txt VARCHAR2);
FUNCTION f_split_str(p_str VARCHAR2, p_division VARCHAR2, p_seq INT)
RETURN VARCHAR2;
PROCEDURE p_rows_column(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_cols IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc);
PROCEDURE p_rows_column_real(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_col IN VARCHAR2,
p_pivot_val IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc);
END;
/
CREATE OR REPLACE PACKAGE BODY pkg_dynamic_rows_column AS
PROCEDURE p_print_sql(p_txt VARCHAR2) IS
v_len INT;
BEGIN
v_len := length(p_txt);
FOR i IN 1 .. v_len / 250 + 1 LOOP
dbms_output.put_line(substrb(p_txt, (i - 1) * 250 + 1, 250));
END LOOP;
END;
FUNCTION f_split_str(p_str VARCHAR2, p_division VARCHAR2, p_seq INT)
RETURN VARCHAR2 IS
v_first INT;
v_last INT;
BEGIN
IF p_seq < 1 THEN
RETURN NULL;
END IF;
IF p_seq = 1 THEN
IF instr(p_str, p_division, 1, p_seq) = 0 THEN
RETURN p_str;
ELSE
RETURN substr(p_str, 1, instr(p_str, p_division, 1) - 1);
END IF;
ELSE
v_first := instr(p_str, p_division, 1, p_seq - 1);
v_last := instr(p_str, p_division, 1, p_seq);
IF (v_last = 0) THEN
IF (v_first > 0) THEN
RETURN substr(p_str, v_first + 1);
ELSE
RETURN NULL;
END IF;
ELSE
RETURN substr(p_str, v_first + 1, v_last - v_first - 1);
END IF;
END IF;
END f_split_str;
PROCEDURE p_rows_column(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_cols IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc) IS
v_sql VARCHAR2(4000);
TYPE v_keep_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_keep v_keep_ind_by;
TYPE v_pivot_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_pivot v_pivot_ind_by;
v_keep_cnt INT;
v_pivot_cnt INT;
v_max_cols INT;
v_partition VARCHAR2(4000);
v_partition1 VARCHAR2(4000);
v_partition2 VARCHAR2(4000);
BEGIN
v_keep_cnt := length(p_keep_cols) - length(REPLACE(p_keep_cols, ',')) + 1;
v_pivot_cnt := length(p_pivot_cols) -
length(REPLACE(p_pivot_cols, ',')) + 1;
FOR i IN 1 .. v_keep_cnt LOOP
v_keep(i) := f_split_str(p_keep_cols, ',', i);
END LOOP;
FOR j IN 1 .. v_pivot_cnt LOOP
v_pivot(j) := f_split_str(p_pivot_cols, ',', j);
END LOOP;
v_sql := 'select max(count(*)) from ' || p_table || ' group by ';
FOR i IN 1 .. v_keep.LAST LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
v_sql := rtrim(v_sql, ',');
EXECUTE IMMEDIATE v_sql
INTO v_max_cols;
v_partition := 'select ';
FOR x IN 1 .. v_keep.COUNT LOOP
v_partition1 := v_partition1 || v_keep(x) || ',';
END LOOP;
FOR y IN 1 .. v_pivot.COUNT LOOP
v_partition2 := v_partition2 || v_pivot(y) || ',';
END LOOP;
v_partition1 := rtrim(v_partition1, ',');
v_partition2 := rtrim(v_partition2, ',');
v_partition := v_partition || v_partition1 || ',' || v_partition2 ||
', row_number() over (partition by ' || v_partition1 ||
' order by ' || v_partition2 || ') rn from ' || p_table;
v_partition := rtrim(v_partition, ',');
v_sql := 'select ';
FOR i IN 1 .. v_keep.COUNT LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
FOR i IN 1 .. v_max_cols LOOP
FOR j IN 1 .. v_pivot.COUNT LOOP
v_sql := v_sql || ' max(decode(rn,' || i || ',' || v_pivot(j) ||
',null))' || v_pivot(j) || '_' || i || ',';
END LOOP;
END LOOP;
IF p_where IS NOT NULL THEN
v_sql := rtrim(v_sql, ',') || ' from (' || v_partition || ' ' ||
p_where || ') group by ';
ELSE
v_sql := rtrim(v_sql, ',') || ' from (' || v_partition ||
') group by ';
END IF;
FOR i IN 1 .. v_keep.COUNT LOOP
v_sql := v_sql || v_keep(i) || ',';
END LOOP;
v_sql := rtrim(v_sql, ',');
p_print_sql(v_sql);
OPEN p_refc FOR v_sql;
EXCEPTION
WHEN OTHERS THEN
OPEN p_refc FOR
SELECT 'x' FROM al WHERE 0 = 1;
END;
PROCEDURE p_rows_column_real(p_table IN VARCHAR2,
p_keep_cols IN VARCHAR2,
p_pivot_col IN VARCHAR2,
p_pivot_val IN VARCHAR2,
p_where IN VARCHAR2 DEFAULT NULL,
p_refc IN OUT refc) IS
v_sql VARCHAR2(4000);
TYPE v_keep_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_keep v_keep_ind_by;
TYPE v_pivot_ind_by IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
v_pivot v_pivot_ind_by;
v_keep_cnt INT;
v_group_by VARCHAR2(2000);
BEGIN
v_keep_cnt := length(p_keep_cols) - length(REPLACE(p_keep_cols, ',')) + 1;
FOR i IN 1 .. v_keep_cnt LOOP
v_keep(i) := f_split_str(p_keep_cols, ',', i);
END LOOP;
v_sql := 'select ' || 'cast(' || p_pivot_col ||
' as varchar2(200)) as ' || p_pivot_col || ' from ' || p_table ||
' group by ' || p_pivot_col;
EXECUTE IMMEDIATE v_sql BULK COLLECT
INTO v_pivot;
FOR i IN 1 .. v_keep.COUNT LOOP
v_group_by := v_group_by || v_keep(i) || ',';
END LOOP;
v_group_by := rtrim(v_group_by, ',');
v_sql := 'select ' || v_group_by || ',';
FOR x IN 1 .. v_pivot.COUNT LOOP
v_sql := v_sql || ' max(decode(' || p_pivot_col || ',' || chr(39) ||
v_pivot(x) || chr(39) || ',' || p_pivot_val ||
',null)) as "' || v_pivot(x) || '",';
END LOOP;
v_sql := rtrim(v_sql, ',');
IF p_where IS NOT NULL THEN
v_sql := v_sql || ' from ' || p_table || p_where || ' group by ' ||
v_group_by;
ELSE
v_sql := v_sql || ' from ' || p_table || ' group by ' || v_group_by;
END IF;
p_print_sql(v_sql);
OPEN p_refc FOR v_sql;
EXCEPTION
WHEN OTHERS THEN
OPEN p_refc FOR
SELECT 'x' FROM al WHERE 0 = 1;
END;
END;
/
如果轉換後的列數很多，建議重新考慮表結構設計。
E. 如何截取一段sql中某個字元串之前的內容，在線等
/****** Sql Server中截取字元串的常用方法 ******/--1、LEFT()方法-----函數說明-----1）語法：LEFT(character,integer) --2）介紹：參數1：要截取的字元串，參數2：截取字元個數--3）使用：--返回從字元串左邊開始指定個數的字元--select LEFT('SqlServer_2008',3)--4）返回：Sql--1、RIGHT()方法----- right()函數說明-----1）語法：RIGHT(character,integer) --2）介紹：參數1：要截取的字元串，參數2：截取字元個數--3）使用：--返回從字元串右邊開始指定個數的字元--select LEFT('SqlServer_2008',4)--4）返回：2008--1、SUBSTRING()方法----- substring()函數說明-----1）語法：SUBSTRING(character,start,length) --2）介紹：參數1：要截取的字元串，參數2：開始截取的下標，參數3：截取的字元長度--3）使用：--返回從字元串中間的字元--select SUBSTRING('SqlServer_2008',4,6)--4）返回：Server
F. 我在PL/SQL中，substr和substrb的效果一樣，怎麼回事
不一樣
比如這兩個
selectsubstr('你好嗎',1,1)fromal;
selectsubstrb('你好嗎',1,1)fromal;第一個有結果，是「你」，第二個就無結果
因為第一個是按字元位來取，從第一位取一位長度
第二個是按位元組來取，對於漢字來說，一個漢字是2個位元組，這樣就取不出東西來了