Example: MAX() with Having Clause Copy SELECTDepartmentId,Max(Salary)DeptMaxSal FROM Employee GROUP BY DepartmentIDHAVINGMAX(Salary)>50000; Get Maximum and Minimum Value In the following example, theMIN()and MAX() functions are used on theSalarycolumn of theEmployeetable. The minimum and maximu...
INSERT INTO tablename (columnlist) VALUES (RowValues1) (RowValues2) (repeat any number of times) 2.3 改 1 2 3 UPDATEtableSET column1=expression1,column2=expression2(repeatanynumberof times)WHERE condition 2.4 删 1 2 3 DELETEFROMtableWHERE condition 删除前可以验证一下: 1 2 3 4 SELECTCOU...
USE sql_store; select *from customerswhere address like ‘%Trail%’ oraddress like ‘%avenue%’LIKE 执行优先级在逻辑运算符之后,毕竟 IN BETWEEN LIKE 本质可看作是比较运算符的简化,应该和比较运算同级,数学→比较→逻辑,始终记住这个顺序,上面这个如果用正则表达式会简单得多 where phone like ‘%9’/wh...
PRINT '--Profiler trace summary--'SELECTtraceid, property,CONVERT(VARCHAR(1024),value)ASvalueFROM::fn_trace_getinfo(default)GOPRINT'--Trace event details--'SELECTtrace_id,status,CASEWHENrow_number =1THENpathELSENULLendASpath,CASEWHENrow_number =1THENmax_sizeELSENULLendASmax_size,CASEWHENrow_...
SQL_MAX_COLUMN_NAME_LEN SQL_MAX_COLUMNS_IN_GROUP_BY SQL_MAX_COLUMNS_IN_INDEX SQL_MAX_COLUMNS_IN_ORDER_BY SQL_MAX_COLUMNS_IN_SELECT SQL_MAX_COLUMNS_IN_TABLE SQL_MAX_CURSOR_NAME_LEN SQL_MAX_IDENTIFIER_LEN SQL_MAX_INDEX_SIZE SQL_MAX_PROCEDURE_NAME_LEN SQL_MAX_ROW_SIZE SQL_MAX_ROW_SIZ...
将limit 20 修改为 limit 30,SQL 如下所示。 select * from waybill_order_added_value_report_detail goodsInfo WHERE ... ORDER BY goodsInfo.id DESC LIMIT 0, 30 \G # 执行用时 2 rows in set (0.06 sec) 执行计划显示当改为 limit 30 时,联合索引生效。 *** 1. row *** id: 1 select...
报错:Update row with Key (id)=(xxxx) multiple times或者duplicate key value violates unique constraint 问题原因:违反唯一性约束,执行UPDATE、INSERT ON CONFLICT或INSERT操作时,主键存在重复数据。 解决方法: 若INSERT语法报错:可以改为INSERT INTO xx ON CONFLICT的语法,实现主键去重,详情请参见INSERT ON CONFLIC...
data_table = Table('data_table', metadata, Column('id', Integer, primary_key=True), Column('data', HSTORE) ) with engine.connect() as conn: conn.execute( data_table.insert(), data = {"key1": "value1", "key2": "value2"} ) HSTORE 提供广泛的操作,包括: 索引操作: data_table...
INSERT INTO tabname [(column [, column...])] VALUES (value [, value...]); 注意: * 插入的数据应与字段的数据类型相同 例如: name列对应的值为字符串,插入的数据类型也应该是字符串类型! * 数据的大小应在列的规定范围内 例如: name列字符长度为10,那么插入的数据长度不能超过10!
WITH `cte` AS ( SELECT `id` FROM `ac_comment` WHERE `post_id` = ? -- 参数绑定 AND STATUS = ? -- 参数绑定 AND `ancestor_id` = ? -- 参数绑定 (例如0,代表根评论) AND `deleted_at` IS NULL -- 注意原始为 IS ?,但逻辑上应为 IS NULL ...