Tag：not
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Solve the problem that not like from set operation to MySQL cannot find null
Remember an interesting discovery: There is a table with 1000 records. Now there is a query statement: #Query statement 1 #Find the field with ‘a’ or ‘B’ or ‘C’ in the ID in the table select * from table1 where id like ‘%A%’ or id like ‘%B%’ or id like ‘%C%’ ; #300 items were […]
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Solve the problem that MySQL uses not in to contain null values
be careful!!! select * from user where uid not in (a,b,c,null); This SQL does not return any results. To avoid null in the list of not in. In addition: – if NULL participates in arithmetic operation, the value of the arithmetic expression is null. (for example: +, -, *, / addition, subtraction, multiplication and division) […]
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SQLite implements operations of if not exist and similar functions
Need to achieve: if not exists(select * from ErrorConfig where Type=’RetryWaitSeconds’) begin insert into ErrorConfig(Type,Value1) values(‘RetryWaitSeconds’,’3′) end Only use: insert into ErrorConfig(Type,Value1) select ‘RetryWaitSeconds’,’3′ where not exists(select * from ErrorConfig where Type=’RetryWaitSeconds’) Because SP is not supported in SQLite Supplement: not in in SQLite3 is not easy to use When I was familiar with SQL […]
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Patient BFC calibration~
Okay, what’s up? Goodmai and om it technology can be printed? Br > 1. BFC rear caliperBFC switch О What? Block formatting contexts removes the following files from the text in the text pane An example in W3C CSS 2.1? It is a wireless transmitter, which fixes the power cable у Unit search, such as […]
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Vs2012 / vs2013 local publishing website problem collection (HTTP error code)
HTTP error 500.19 internal server error, HTTP error 403.14 forbidden, HTTP error 404.17 not found. The specific contents are as follows 1. Unable to read configuration file due to insufficient permissions resolvent:Right click the website and select Edit permission. Security – Edit – add – Advanced – find now – everyone. 2. Missing site default […]
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Centos5 executes the host prompt command not found solution
When – bash: host: command not found is displayed, we need to install the corresponding package The host program is in the bind utils package terms of settlement So install bind utils first Copy code The code is as follows: yum install bind-utils summary Many default packages will not be installed, so you must first […]
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Visit the website to prompt 404 not found what to do 404 not found repair methods
You may have seen a “404 not found” reminder in the process of accessing web pages on your computer. What does 404 not found mean? How do I fix 404 not found? Let’s have a look. Visit the website to prompt 404 not found what to do 404 not found repair method: What does 404 […]
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CKB test network? After Rylai’s visit, he can leave some money
For example, 5? 18. It’s commonNervos CKB test set up cable/ a> The following is the main aspect of the survey. Rylai was the first person to ask for the first place, the first person to ask for the first place, the first person to ask for the first place, the first person to ask […]
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Prompt for CentOS to execute FTP command ftp:command not Find solutions
When using CentOS, you need to use FTP to upload files, but when you get to the FTP command of the script, you will make an error Copy code The code is as follows: ftp: command not found If the FTP client is not installed, you need to re install itThe solution is to go […]
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Solve “unable to access” https://gitee.com/ Own project / ‘: could not resolve host: gitee.com problem
Yesterday, the company’s network replacement, and then in the use of GIT operation code, encountered the problem described in the title. Only in this paper, the solution process of the problem is recorded. First step: Get the IP address of this machine. Step 2: Ping The connection is normal. Step 3: Find the hosts file […]
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Solution to the problem that not in is null in MySQL
Some time ago, when I was doing a small function in the company, I counted the number of data in a certain situation and then modified the problem. At that time, I thought it was very simple. I wrote the following SQL: SELECT COUNT(*) FROM t1 where tl.c1 not IN (SELECT t2.c1 FROM t2); The […]
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Detailed explanation of the impact of not exists on external layer query in Oracle
Preface Recently, my colleagues found a problem: the buffer get in 12C is very high, but the buffer get in 10g is very low. Doubt there is a problem with the optimizer of 12C. In this 10g environment and 12C environment, the amount of data is roughly the same, but there are only a few […]