ORACLE变量定义及使用（另，T-SQL EXISTS的PLSQL替代写法）

1. 简单变量
declare v_cnt NUMBER(10,0) := 0;
BEGIN
SELECT COUNT(1) INTO v_cnt FROM concept.Decoction WHERE DecoctionId = -1;
IF v_cnt = 0 THEN
insert into concept.Decoction( DecoctionId, Code, Name, MnemonicCode, SpellCode, WBCode, ClinicItemId, IsSpecial, IsDeleted, RowVersion, IsNeedAccount ) values
( -1, NULL, NULL, Null, NULL, NULL, -1, 0, 0, SYSDATE, 0 );
END IF;
END;

2. 以表的字段类型定义的变量
create table DBO.TEST_TBL
(
ID NUMBER(10) NOT NULL PRIMARY KEY
);
declare v_cnt CONCEPT.decoction.DecoctionId%type := 0;
BEGIN
SELECT DecoctionId INTO v_cnt FROM concept.Decoction WHERE DecoctionId = -1;
INSERT INTO DBO.TEST_TBL SELECT v_cnt from dual;
END;
select * from DBO.TEST_TBL;

3. 以表的行定义的变量
drop table DBO.TEST_TBL;
create table DBO.TEST_TBL
(
ID NUMBER(10) NOT NULL PRIMARY KEY
);
declare v_row CONCEPT.decoction%rowtype;
BEGIN
SELECT * INTO v_row FROM concept.Decoction WHERE DecoctionId = -1;
INSERT INTO DBO.TEST_TBL SELECT v_row.DecoctionId from dual;
END;
select * from DBO.TEST_TBL;

4. 以记录类型定义的变量
drop table DBO.TEST_TBL;
create table DBO.TEST_TBL
(
ID NUMBER(10) NOT NULL PRIMARY KEY,
NAME nvarchar2(50)
);

declare
type v_flds is record(
ID concept.Decoction.DecoctionId%type,
NAME concept.Decoction.Name%type);
v_row v_flds;
BEGIN
SELECT DecoctionId,Name INTO v_row FROM concept.Decoction WHERE DecoctionId = 62;
INSERT INTO DBO.TEST_TBL SELECT v_row.ID, v_row.NAME from dual;
END;
select * from DBO.TEST_TBL;