sql-update

问题 I am trying to understand how to safely increment a counter column, that may be incremented simultaneously by many users (It's a Web API for a mobile app). I've read the popular questions in SO for strategies dealing with the issue but I can't seem to figure what's wrong with using a simple: UPDATE Table SET Counter = Counter + 1 I've built the following code sample to try and get inconsistent values and prove myself that using only this simple update statement is not good practice: class

问题 I have the following table in SQL Server called tblProducts : +-----------+--------------+-------------+ | pkProduct | fkProductID | intIssue | +-----------+--------------+-------------+ | 1 | 10 | 1 | | 2 | 10 | 2 | | 3 | 10 | 4 | | 4 | 11 | 1 | | 5 | 11 | 2 | | 6 | 11 | 3 | | 7 | 11 | 5 | | 8 | 12 | 1 | | 9 | 13 | 1 | | 10 | 13 | 4 | | 11 | 14 | 1 | | 12 | 14 | 3 | | 13 | 14 | 6 | | 14 | 15 | 1 | | 15 | 16 | 1 | +-----------+--------------+-------------+ Over time, with rows having being

问题 What is the syntax to UPDATE a BLOB field in an existing SQLite record, using Python? I create a 13x13 array of floats and want to Update a specific record (i.e. using a WHERE clause) in my table with that array. What is the proper UPDATE syntax? The array has the following form: [ 4.65640926e+00 5.59250259e+00 5.28963852e+00 1.60680866e+00 -3.39492680e-01 -4.76834650e-01 -4.76834650e-01 -2.29132240e-01 1.49733067e+00 1.51563072e+00 1.49733067e+00 9.53471420e-01 -1.40306473e+00] [ 5.28963852e

问题 I have a table and in this table i have data is not properly loaded data integrity issue ,since this is a dimension table we need to maintain the effective_dt_from and effective_dt_to and version correctly ,below is the table and sample data create table TEST ( LOC_SID NUMBER(38,0), CITY VARCHAR2(180 BYTE), POSTAL_CD VARCHAR2(15 BYTE), EFFECTIVE_DT_FROM DATE, EFFECTIVE_DT_TO DATE, VERSION NUMBER(38,0) ); Insert into TEST values (25101,'Assam',1153,to_date('01.01.00 00:00:00','DD.MM.YY HH24:MI

问题 I like to add event duration to a previous record every time a new record gets added. This is what I have ID EventType EventTime EventDuration ------------------------------------- 1 TypeA 10:20 NULL 2 TypeB 09:30 NULL 3 TypeC 08:00 NULL This is what I want to achieve: ID EventType EventTime EventDuration ------------------------------------- 1 TypeA 10:20 00:50 2 TypeB 09:30 01:30 3 TypeC 08:00 ... 4 ... ... When a new records gets added (with ID, EventType and EventTime), the duration of

问题 I like to add event duration to a previous record every time a new record gets added. This is what I have ID EventType EventTime EventDuration ------------------------------------- 1 TypeA 10:20 NULL 2 TypeB 09:30 NULL 3 TypeC 08:00 NULL This is what I want to achieve: ID EventType EventTime EventDuration ------------------------------------- 1 TypeA 10:20 00:50 2 TypeB 09:30 01:30 3 TypeC 08:00 ... 4 ... ... When a new records gets added (with ID, EventType and EventTime), the duration of

问题 Trying to run a update script on a table, but getting an error: ERROR: column "ok" does not exist LINE 2: SET first_name="ok", last_name="pk", email="ooo", phone="... CREATE TABLE employee ( employee_id SERIAL PRIMARY KEY, first_name varchar(255) NOT NULL, last_name varchar(255) NOT NULL, email varchar(255) NOT NULL, phone varchar(255) ); INSERT INTO employee( first_name, last_name, email, phone) VALUES ('Kyle', 'Belanger', 'kbelanger@ok.com', '(240) 298-4664'); UPDATE "employee" SET first

问题 I have a script written in PHP which has this line which is working correctly for selecting the data i need; $result = mysql_query("SELECT product_name, sku, qty FROM supplier_dropship_items WHERE supplier_id = '3' AND status = '2'", $db_beb); What I'm struggling with is a way to update the records I have selected, once selected I need to change the status = '1' so that the next time my script runs it won't pull the same data in the select and will only pull new items in the table which have

问题 I have a script written in PHP which has this line which is working correctly for selecting the data i need; $result = mysql_query("SELECT product_name, sku, qty FROM supplier_dropship_items WHERE supplier_id = '3' AND status = '2'", $db_beb); What I'm struggling with is a way to update the records I have selected, once selected I need to change the status = '1' so that the next time my script runs it won't pull the same data in the select and will only pull new items in the table which have

问题 I have table A with product_id,cost,year,quarter,... etc columns. I have another table B with product_id,base_cost,current_year,p_year,p_quarter,p_order columns. I want to write an update query to update A from B. My conditions are - WHERE A.product_id=B.product_id and A.year=B.current_year and (A.year=B.p_year and A.quarter>B.p_quarter) or A.year>B.p_year and A.cost=0; But the problem is, with these conditions if i have more than one rows in B then i only want to update from the row of B