在MySQL 中,插入(insert)一条记录很简单,但是一些特殊应用,在插入记录前,需要检查这条记录是否已经存在,只有当记录不存在时才执行插入操作,本文介绍的就是这个问题的解决方案 example 代码
empid, shipcountry, freight)VALUES(3,11, N'USA',10.00);INSERTINTOSales.MyOrders(custid, empid, orderdate, shipcountry, freight)VALUES(3,17,DEFAULT, N'USA',30.00);--multiple rowsINSERTINTOSales.MyOrders
firstName, lastName) // (1) .from(person) .where(); // (2) if (targetId != null) { // (3) builder .and(id, isEqualTo(targetId)); } else { builder .and(firstName, isLike(fName).filter(Objects::nonNull).map(s -> "%" + s + "%")) // (...
5. Not using temporary tables for complex queries SQL would be great if only we could debug queries. What if I told you can debug them! You can breakdown a complex query and create multiple temporary tables. Then you can run “sanity check” queries against those tables to make sure they...
insert into tb_user (username, password) select #{user.username}, #{user.password} where ...
theFROMclause of a query as if it were a table name. TheOPENROWSETfunction can also be referenced as the target table of anINSERT,UPDATE, orDELETEstatement, subject to the capabilities of the OLE DB provider. Although the query might return multiple result sets,OPENROWSETreturns only the first...
SQL_CA2_MAX_ROWS_INSERT = 当游标是动态游标时,SQL_ATTR_MAX_ROWS语句属性会影响 INSERT 语句。SQL_CA2_MAX_ROWS_DELETE = 当游标是动态游标时,SQL_ATTR_MAX_ROWS语句属性会影响 DELETE 语句。SQL_CA2_MAX_ROWS_UPDATE = 当游标是动态游标时,SQL_ATTR_MAX_ROWS语句属性会影响 UPDATE 语句。SQL_CA2_MAX_...
IF RULE COLLATE IN SAVE COLUMN INDEX SCHEMA COMMIT INNER SECURITYAUDIT COMPUTE INSERT SELECT CONSTRAINT INTERSECT SESSION_USER CONTAINS INTO SET CONTAINSTABLE IS SETUSER CONTINUE JOIN SHUTDOWN CONVERT KEY SOME CREATE KILL STATISTICS CROSS LEFT
If rows are that wide, the Database Engine produces an error during query execution. By using ROBUST PLAN, you instruct the Query Optimizer not to consider any query plans that might run into this problem. If such a plan isn't possible, the Query Optimizer returns an error instead of ...
SQL20020NOperationoperation-typeis not valid for typed tables. Explanation The operation identified byoperation-typecannot be performed on a typed table. The statement cannot be processed. User response If it is an ALTER statement, remove the ADD COLUMN clause, ADD PERIOD clause, or SET DATATYPE...