SQL中update与update select结合语法详解与实例 |
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SQL中update与update select结合语法详解与实例
1、通用update
一般简单的update语法比较通用 语法： UPDATE table_name SET column1=value1, column2=value2, ... WHERE some_column = some_value;注：若不加where条件则是更新表中的所有数据， 故执行没有where子句的update要慎重再慎重。 实例： UPDATE subject SET name='数学', type='理学' WHERE id = 1; 2、GreenPlum update与select结合 语法： UPDATE [only] table [[as] alias] SET {column = {expression | default} | (column [, ...]) = ({expression | default}[, ...])}[, ...] [FROM fromlist] [WHERE condition | WHERE current of cursor_name];注：若不加where条件则是更新表中的所有数据， 故执行没有where子句的update要慎重再慎重。 实例： UPDATE table1 t1 SET column1 = t2.columnname1 column2 = t2.columnname2 FROM (select columnname1,columnname2 from table2) t2 WHERE t1.column3 = t2.column3 AND t1.column = '111';注：对于set列中左边的列不能使用t1.这种别名方式，只能使用column名称 PostgreSQL与GreenPlum语法基本一致 3、MySQL update与select结合 第一种： 语法： UPDATE table1 SET column1 = (SELECT column FROM table2 [WHERE condition]) WHERE table1.column2 = value;注：若不加where条件则是更新表中的所有数据， 故执行没有where子句的update要慎重再慎重。 实例： UPDATE tb_bookcase SET name = (SELECT bookname FROM tb_bookinfo WHERE tb_bookinfo.type = tb_bookcase.type AND tb_bookinfo.ord_date IN (SELECT MAX(ord_date) FROM tb_bookinfo)) WHERE tb_bookcase.subject = '理学'; 第二种： 语法： UPDATE table1 inner/left/right join table2/(select columns from table3 [inner/left/right join on condition] [where conditions]) as t3 ON condition SET column1 = value1,column2 = value2,... [WHERE conditions]; 实例： 例1： UPDATE $table1 a INNER JOIN $table2 b ON a.user_id = b.user_id SET a.balance = a.balance + b.income,b.status= 1 WHERE b.id = 5 AND b.status = 0； 例2： UPDATE A INNER JOIN (SELECT B.B1 as B1,B.B2 as B2,C.C1 as C1 from B LEFT JOIN C on B.B3=C.C3) as t ON A.A3=t.B1 set A.A1=t.B2, A.A2=t.C1; UPDATE tb_bookcase INNER JOIN (SELECT tb_bookinfo.rid as rid,tb_bookinfo.bookname,department.name LEFT JOIN department on tb_bookinfo.depid=department.id) as t ON tb_bookcase.id=t.rid set tb_bookcase.bookname=t.bookname, tb_bookcase.departname=t.name ; 4、Oracle update与select结合 语法： UPDATE table1 alias SET (column_name,column_name ) = ( SELECT column_name, column_name FROM table2 WHERE table2.column_name = alias.column_name) [WHERE column_name = VALUE]注：若不加where条件则是更新表中的所有数据， 故执行没有where子句的update要慎重再慎重。 实例： 例1： UPDATE t_order t1 SET (ordername,orderprice) = (SELECT detailname,totalprice FROM t_detail WHERE t_detail.detailclasses = t1.classes) WHERE t1.orderid = 1 例2： UPDATE A SET (A1, A2, A3) = (SELECT B1, B2, B3 FROM B WHERE A.ID = B.ID) WHERE ID IN (SELECT B.ID FROM B WHERE A.ID = B.ID) 5、SQLServer update与select结合 语法： UPDATE table1 SET column1 = t2.column1, column1 = t2.column2, ... FROM table1 INNER/LEFT/RIGHT JOIN table2 ON table1.column = table2.column [WHERE conditions]注：若不加where条件则是更新表中的所有数据， 故执行没有where子句的update要慎重再慎重。 实例： UPDATE A SET A1 = t2.B2 , A2 = t2.C1 FROM A INNER JOIN ( SELECT B.B1,B.B2,C.C1 FROM B left join C on B.B3 = C.C3) t2 ON A.A3 = t2.B1 WHERE A.A4 = 1; UPDATE t_abnormal_fee SET order_code = t2.order_code , return_fee = t2.express_fee FROM t_abnormal_fee INNER JOIN ( SELECT t_order.id,t_order.order_code,t_detail.express_fee FROM t_order left join t_detail on t_order.name = t_detail.name) t2 ON t_abnormal_fee.id = t2.id WHERE t_abnormal_fee.id = 1; |
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