我有这样的数据：
studyID | participantID | question | problems
1 | 1 | A100 | 3
1 | 1 | A200 | 2
1 | 1 | A300 | 4
1 | 1 | B100 | 2
1 | 1 | B200 | 5
1 | 2 | A100 | 3
1 | 2 | A200 | 3
1 | 2 | A300 | 3
1 | 2 | B100 | 1
1 | 2 | B200 | 6
我想要像这样的输出
section | num questions| total problems | average problems
A | 3 | 18 | 6
B | 2 | 14 | 7
sql fiddle中的代码如下所示：
SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL,ALLOW_INVALID_DATES';
CREATE SCHEMA `interviewcodes` DEFAULT CHARACTER SET utf8 ;
USE `interviewcodes` ;
CREATE TABLE `interviewerlkup` (
`InterviewerID` INT(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`InterviewerID`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `studylkup` (
`StudyID` INT(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`StudyID`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `studyinterviewers` (
`StudyID` INT(11) NOT NULL,
`InterviewerID` INT(11) NOT NULL,
PRIMARY KEY (`StudyID`, `InterviewerID`),
INDEX `fk_StudyInterviewers_InterviewerLkup1_idx` (`InterviewerID` ASC),
CONSTRAINT `fk_StudyInterviewers_InterviewerLkup1`
FOREIGN KEY (`InterviewerID`)
REFERENCES `interviewcodes`.`interviewerlkup` (`InterviewerID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_StudyInterviewers_StudyLkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `participant` (
`ParticipantID` INT(11) NOT NULL AUTO_INCREMENT,
`ParticipantCaseID` VARCHAR(45) NOT NULL,
`StudyID` INT(11) NOT NULL,
`InterviewerID` INT(11) NOT NULL,
PRIMARY KEY (`ParticipantID`),
INDEX `fk_participant_studyinterviewers1_idx` (`InterviewerID` ASC),
CONSTRAINT `fk_participant_studyinterviewers1`
FOREIGN KEY (`InterviewerID`)
REFERENCES `interviewcodes`.`studyinterviewers` (`InterviewerID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_participant_studylkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `coderlkup` (
`CoderID` INT(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`CoderID`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `studycoders` (
`StudyID` INT(11) NOT NULL,
`CoderID` INT(11) NOT NULL,
PRIMARY KEY (`StudyID`, `CoderID`),
INDEX `fk_StudyCoders_CoderLkup1_idx` (`CoderID` ASC),
CONSTRAINT `fk_StudyCoders_CoderLkup1`
FOREIGN KEY (`CoderID`)
REFERENCES `interviewcodes`.`coderlkup` (`CoderID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_StudyCoders_StudyLkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `studyquestion` (
`StudyQuestionLabel` VARCHAR(45) NOT NULL,
`StudyID` INT(11) NOT NULL,
PRIMARY KEY (`StudyQuestionLabel`, `StudyID`),
CONSTRAINT `fk_StudyQuestion_StudyLkup`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE `codedata` (
`StudyID` INT(11) NOT NULL,
`ParticipantID` INT(11) NOT NULL,
`CoderID` INT(11) NOT NULL,
`StudyQuestionLabel` VARCHAR(45) NOT NULL,
`TotalScore` INT(11) NULL DEFAULT 0,
INDEX `fk_CodeData_Participant1_idx` (`ParticipantID` ASC),
INDEX `fk_CodeData_StudyCoders1_idx` (`CoderID` ASC),
INDEX `fk_codedata_studyquestion1_idx` (`StudyQuestionLabel` ASC),
PRIMARY KEY (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`),
CONSTRAINT `fk_CodeData_Participant1`
FOREIGN KEY (`ParticipantID`)
REFERENCES `interviewcodes`.`participant` (`ParticipantID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_CodeData_StudyCoders1`
FOREIGN KEY (`CoderID`)
REFERENCES `interviewcodes`.`studycoders` (`CoderID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_codedata_studylkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_codedata_studyquestion1`
FOREIGN KEY (`StudyQuestionLabel`)
REFERENCES `interviewcodes`.`studyquestion` (`StudyQuestionLabel`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;
INSERT INTO `studylkup` (`StudyID`) VALUES ('3');
INSERT INTO `interviewerlkup` (`InterviewerID`) VALUES ('1');
INSERT INTO `interviewerlkup` (`InterviewerID`) VALUES ('2');
INSERT INTO `coderlkup` (`CoderID`) VALUES ('1');
INSERT INTO `coderlkup` (`CoderID`) VALUES ('2');
INSERT INTO `studyinterviewers` (`StudyID`, `InterviewerID`) VALUES ('3', '2');
INSERT INTO `studyinterviewers` (`StudyID`, `InterviewerID`) VALUES ('3', '1');
INSERT INTO `studycoders` (`StudyID`, `CoderID`) VALUES ('3', '2');
INSERT INTO `studycoders` (`StudyID`, `CoderID`) VALUES ('3', '1');
INSERT INTO `participant` (`ParticipantID`, `ParticipantCaseID`, `StudyID`, `InterviewerID`) VALUES ('1', 'AJW123', '3', '2');
INSERT INTO `participant` (`ParticipantID`, `ParticipantCaseID`, `StudyID`, `InterviewerID`) VALUES ('3', 'AJW125', '3', '1');
INSERT INTO `studyquestion` (`StudyQuestionLabel`, `StudyID`) VALUES ('A100', '3');
INSERT INTO `studyquestion` (`StudyQuestionLabel`, `StudyID`) VALUES ('A200', '3');
INSERT INTO `studyquestion` (`StudyQuestionLabel`, `StudyID`) VALUES ('A300', '3');
INSERT INTO `studyquestion` (`StudyQuestionLabel`, `StudyID`) VALUES ('B100', '3');
INSERT INTO `studyquestion` (`StudyQuestionLabel`, `StudyID`) VALUES ('B200', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '1', '1', 'A100', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '1', '1', 'A200', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '1', '1', 'A300', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '1', '1', 'B100', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '1', '1', 'B200', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '3', '2', 'A100', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '3', '2', 'A200', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '3', '2', 'A300', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '3', '2', 'B100', '3');
INSERT INTO `codedata` (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`, `TotalScore`) VALUES ('3', '3', '2', 'B200', '3');
更新
我试过了：
print("<table align = 'center' border = '2'>");
print("<tr>");
print("<td align = 'center'>Section</td>");
print("<td align = 'center'>Total Number of Items</td>");
print("<td align = 'center'>Total Number of Problems</td>");
print("<td align = 'center'>Average Number of Problems</td>");
print("</tr>");
$sql1 = "SELECT LEFT(codedata.StudyQuestionLabel, 1) as Section,
COUNT(*) as NumQuestions,
SUM(codedata.TotalScore) as TotalProblems,
AVG(codedata.TotalScore) as AvgProblems
FROM interviewcodes.codedata codedata
WHERE (codedata.StudyID = ".$StudyID.")
GROUP BY LEFT(codedata.StudyQuestionLabel, 1)
ORDER BY LEFT(codedata.StudyQuestionLabel, 1) ASC;";
// run query and get result set
$rs1 = $conn->query($sql1);
// check if query1 is wrong;
if ($rs1 == false)
{
$errmsg = "Wrong SQL1: ".$sql1."Error: ".$conn->error;
trigger_error($errmsg, E_USER_ERROR);
}
else
{
while ($arr1 = $rs1->fetch_array(MYSQLI_ASSOC))
{
print_r($arr1);
print("<tr>");
print("<td align = 'center'>".$arr1['Section']."</td>");
print("<td align = 'center'>".$arr1['NumQuestions']."</td>");
print("<td align = 'center'>".$arr1['TotalProblems']."</td>");
print("<td align = 'center'>".$arr1['AvgProblems']."</td>");
print("</tr>");
}
}
print('</table>');
我稍微修改了上面的代码，得到了下面的输出。
section | num questions| total problems | average problems
A | 6 | 18 | 3
B | 4 | 14 | 3.5
我想要这个：
section | num questions| total problems | average problems
A | 3 | 18 | 6
B | 2 | 14 | 7
它似乎在计算每一条以字母a开头的问题的记录，而我真正想要的是它计算以字母a开始的不同问题。我该怎么做？
在SQL中，substr()从1开始计数，而不是从0开始计数。在任何情况下，您都可以使用left()函数，而不必担心：
SELECT LEFT(Question, 1) as section, COUNT(*) as numQuestions, SUM(Problems) as totalProblems
FROM codedata
WHERE (StudyID = ".$StudyID.")
GROUP BY LEFT(Question, 1);
您也可以添加您似乎也想要的配给，或者使用avg()函数：
SELECT LEFT(Question, 1) as section, COUNT(*) as numQuestions, SUM(Problems) as totalProblems,
AVG(Problems) as averageProblems
FROM codedata
WHERE (StudyID = ".$StudyID.")
GROUP BY LEFT(Question, 1);