1 00:00:00,720 --> 00:00:02,250 Hello and welcome. 2 00:00:02,270 --> 00:00:16,770 Came this video we will be using the rescue ELDs cell lect command to read and filter data from a database 3 00:00:17,370 --> 00:00:18,870 because Q Was there live. 4 00:00:18,880 --> 00:00:23,760 Mine is the busiest off or the school commands. 5 00:00:23,850 --> 00:00:26,080 It's the one you used. 6 00:00:26,130 --> 00:00:32,370 Mostly cause it's the one you need to retrieve data from a database. 7 00:00:32,490 --> 00:00:42,870 Is why you need to read relevant information from a database so the rescue select statement I would 8 00:00:42,870 --> 00:00:54,190 see you would use almost 60 or 70 percent more than the other rescue a select command. 9 00:00:54,280 --> 00:01:02,730 Ask you also what command all saw works with other parts of the obscure language. 10 00:01:02,730 --> 00:01:13,020 It also works in combination with the WHERE clause they where clause is used to act as a filter to filter 11 00:01:13,410 --> 00:01:17,900 the data that is returned by the select command. 12 00:01:18,150 --> 00:01:28,440 All saw you have the order by the order by can be used to use the date that has been retrieve puts them 13 00:01:28,500 --> 00:01:31,950 in some kind of sorting order. 14 00:01:31,980 --> 00:01:41,460 So this has got the leg is used in combination with all the key words like the WHERE clause and the 15 00:01:41,550 --> 00:01:42,730 Order barc. 16 00:01:42,750 --> 00:01:52,530 So we are going to use it as glue a Select Tool or pull information out of a database and also use the 17 00:01:52,580 --> 00:02:01,140 other clauses like the WHERE clause and the order by to field to the information that is returned from 18 00:02:01,140 --> 00:02:02,650 the database. 19 00:02:02,750 --> 00:02:12,830 We are going to use this select command to view data from the employees table the employees table is 20 00:02:12,840 --> 00:02:21,740 a table in the char scheme so I have called or a call to add 24 hour edit or open. 21 00:02:21,810 --> 00:02:30,150 Were going to use this to query and retrieve some information from the database table so to do that 22 00:02:30,150 --> 00:02:42,290 you use the Select keyword you type in select and then hysterics Asterix means bring back all the columns 23 00:02:42,300 --> 00:02:47,520 so bring back everything and then into a front. 24 00:02:48,060 --> 00:02:51,530 You need to specify where you get the data from. 25 00:02:51,690 --> 00:02:52,840 So are you from. 26 00:02:52,960 --> 00:02:57,120 Will specified the table and the table name its employees 27 00:02:59,690 --> 00:03:02,310 and they up with a semicolon. 28 00:03:02,550 --> 00:03:03,120 So what. 29 00:03:03,130 --> 00:03:11,280 This skill on combined this saying is that bringing back all the records from this table I want order 30 00:03:11,310 --> 00:03:13,480 columns or the rows. 31 00:03:13,590 --> 00:03:20,730 So by using this as serax here you are specify you want everything returned. 32 00:03:20,730 --> 00:03:24,250 No data filter just bring back everything. 33 00:03:24,510 --> 00:03:25,800 So fact execute. 34 00:03:25,830 --> 00:03:29,950 This is was retimed everything from that table. 35 00:03:30,180 --> 00:03:37,470 These are all the columns from the table and the tables got three hundred and seven rows in total. 36 00:03:37,470 --> 00:03:39,730 So is back everything. 37 00:03:39,840 --> 00:03:45,730 So the select statement can be used to retrieve data from a table. 38 00:03:45,960 --> 00:03:53,790 But they can also be used to filter the information that is returned from the table. 39 00:03:53,790 --> 00:04:02,910 You can also specify specific information you want and then bring back everything to do that you have 40 00:04:02,910 --> 00:04:17,520 to use with clocks or write say we've had a request to find out how many employees earn more than twelve 41 00:04:17,850 --> 00:04:21,420 thousand dollars or pounds a year. 42 00:04:21,690 --> 00:04:28,720 So the seller let come out is what we'll use to get that information. 43 00:04:28,740 --> 00:04:36,960 We also need to use the where clause to act as a filter so that we don't get all the data returned and 44 00:04:36,960 --> 00:04:43,520 then we need to put data in some kind of order using the order by command. 45 00:04:43,780 --> 00:04:50,260 So the data we need query we need to write this. 46 00:04:50,530 --> 00:04:56,800 We do select. 47 00:04:59,000 --> 00:04:59,750 We meet us. 48 00:05:00,130 --> 00:05:06,600 Ify the column names so we wonder first name last name and salary. 49 00:05:06,600 --> 00:05:09,910 All right so go first name. 50 00:05:12,120 --> 00:05:16,490 Always write the columns the way they'll specify on the table. 51 00:05:16,490 --> 00:05:19,790 This is the first name you see is caught on the score. 52 00:05:20,090 --> 00:05:26,630 And then you separate the columns with a comma sort of first column his first name and the last name 53 00:05:26,630 --> 00:05:27,550 as well here. 54 00:05:27,790 --> 00:05:29,180 So you type your last name 55 00:05:32,930 --> 00:05:39,160 comma and then next one salary. 56 00:05:39,280 --> 00:05:45,390 All right you don't need a comma with a last column just the columns that precede that. 57 00:05:45,410 --> 00:05:48,640 So I've got all the columns I want next. 58 00:05:48,710 --> 00:05:56,500 I need to specify from what table table name is employees. 59 00:05:59,060 --> 00:06:04,420 And then I need to add a to cause I don't want all the records returned. 60 00:06:04,490 --> 00:06:13,100 So you use a where clause 2 and a filter where salary 61 00:06:16,130 --> 00:06:23,870 remember the request was for data relating to people who earn more than 12000 Dulux. 62 00:06:23,960 --> 00:06:28,300 So where's salary is greater. 63 00:06:28,340 --> 00:06:31,990 This is doing great and downsizing this symbol here. 64 00:06:32,000 --> 00:06:35,330 So where is salary is greater than 12000. 65 00:06:39,640 --> 00:06:40,180 Okay. 66 00:06:40,180 --> 00:06:46,480 So was this this was this daytime's return we need to filter it. 67 00:06:46,510 --> 00:06:48,160 So you used the order by 68 00:06:50,830 --> 00:06:52,840 order by salary 69 00:06:55,780 --> 00:07:01,710 descending descending means once you returned the salary. 70 00:07:01,850 --> 00:07:06,700 I want you to filter it or order it in a sense in descending order. 71 00:07:06,710 --> 00:07:10,370 Now this from high to low. 72 00:07:10,370 --> 00:07:11,010 All right. 73 00:07:11,030 --> 00:07:20,940 We end this statement with a semicolon So the whole lot of this is known as Eskew will query or statement. 74 00:07:21,240 --> 00:07:27,700 The entire block here highlighted is known as an obscure query or statement. 75 00:07:27,700 --> 00:07:35,870 So now I can execute that and is giving me a total total of eight rules. 76 00:07:35,920 --> 00:07:44,560 So there are eight people in this organization in the Employees Table that earn more than twelve thousand 77 00:07:44,560 --> 00:07:46,160 dollars each year. 78 00:07:46,540 --> 00:07:53,940 So I'll commit the day to comment that to date I now committed to the table. 79 00:07:53,950 --> 00:08:00,620 So I've got this information so to export this information to someone else. 80 00:08:00,630 --> 00:08:04,950 I just go to export data set. 81 00:08:05,500 --> 00:08:15,490 You type in the name you give in the type of format so you can export it as an Excel file or hastier 82 00:08:15,490 --> 00:08:16,960 mail any of this relevant. 83 00:08:16,960 --> 00:08:22,950 Once I get weichsel I give in name of salary's and click balki. 84 00:08:23,590 --> 00:08:29,340 So if I open my desktop I should have afford a cord sub. 85 00:08:29,600 --> 00:08:36,580 So this is the spreadsheet that was extracted from the table so I opened this up. 86 00:08:39,840 --> 00:08:40,580 And there you go. 87 00:08:40,570 --> 00:08:47,670 So that's the dust the record of eight people who earn more than twelve thousand dollars. 88 00:08:47,820 --> 00:08:57,070 So I can now email this spreadsheet to the finance director or wherever I requested that information. 89 00:08:57,090 --> 00:09:02,970 So this is how you would retrieve data from the database. 90 00:09:02,970 --> 00:09:04,720 So in this feed you. 91 00:09:04,770 --> 00:09:13,980 We use this rescue us select key word command to retrieve data from a database table. 92 00:09:13,980 --> 00:09:24,750 We all saw filtered data use in the where clause and then put the data in salary order in distending 93 00:09:24,750 --> 00:09:29,960 way from high to low using the order by clause. 94 00:09:30,030 --> 00:09:30,800 So it is. 95 00:09:30,810 --> 00:09:35,350 By here you can order by any on the table columns more. 96 00:09:35,370 --> 00:09:39,890 In this case I have ordered by the salary sense. 97 00:09:39,960 --> 00:09:48,840 The salary is ordered in the order of specified descend in taxes from high to low. 98 00:09:49,080 --> 00:09:52,170 I hold information in his view has been helpful. 99 00:09:52,350 --> 00:10:02,420 So you should be able to use the as Google com said Let command to retrieve data from a database. 100 00:10:02,610 --> 00:10:04,740 Thank you so much for watching. 101 00:10:04,740 --> 00:10:05,430 Take care. 102 00:10:05,430 --> 00:10:06,360 Bye for now. 103 00:10:06,370 --> 00:10:09,540 TRAMP practice as much as you can. 104 00:10:09,660 --> 00:10:15,260 Please feel free to contact me if you've got any issues relating to these. 105 00:10:15,390 --> 00:10:16,720 Feed your course. 106 00:10:16,770 --> 00:10:17,790 Thanks so much. 107 00:10:17,790 --> 00:10:18,590 Bye for now.