INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
    CASE 
    WHEN @ContractType = '1' THEN
        SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
        FROM BS_Contract AS A left join OA_Consumer AS B ON A.First = B.ID
        WHERE A.ID = @ContractID
    WHEN @ContractType = '0' THEN
        SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
        FROM BS_Contract_AUDIT AS A left join OA_Consumer AS B ON A.First = B.ID
        WHERE A.ID = @ContractID
    ELSE
        SELECT '','','','',NULL,'',''
    END

if @ContractType = '1' 
begin
    INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
     SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
        FROM BS_Contract AS A left join OA_Consumer AS B ON A.First = B.ID
        WHERE A.ID = @ContractID
end
else
begin
    if  @ContractType = '0'
    begin
        INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
           SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
            FROM BS_Contract_AUDIT AS A left join OA_Consumer AS B ON A.First = B.ID
            WHERE A.ID = @ContractID
    end
    else
    begin
     INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
     SELECT '','','','',NULL,'',''
    end
end

------解决方案--------------------

SQL code
if @ContractType = '1' 
insert into ...
if @ContractType = '0'
insert into ...

------解决方案--------------------

SQL code
IF ContractType = '1'
INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
    SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
    FROM BS_Contract AS A left join OA_Consumer AS B ON A.First = B.ID
    WHERE A.ID = @ContractID
ELSE IF  @ContractType = '0' 
INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState)
    SELECT a.ContractCode,a.SD_State_InOut,a.ContractName,a.AlterMoney,a.SignDate,a.ContractState,b.ConsumerName AS First_Map 
    FROM BS_Contract_AUDIT AS A left join OA_Consumer AS B ON A.First = B.ID
ELSE 
INSERT INTO @tabResult (ContractCode,SD_State_InOut,First_Map,ContractName,AlterMoney,SignDate,ContractState) 
    SELECT '','','','',NULL,'',''

------解决方案--------------------
不支持你这种写法，改为if语句

------解决方案--------------------
这种case when 是对的

case when 的结果只是一个值 不能是一个集合

------解决方案--------------------
1,用if else
2.  
insert into xxxx select xxxx from xxx where xxx  and @contractType='1';
insert into xxxx select xxx from xxxx where xxx  and @contractType='0';


------解决方案--------------------
楼上正解  用if判断

------解决方案--------------------