What do those colons in the sqlite command mean?

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See below code snippet, I wonder what the colons (':') in the SQLite statements mean. I studied at SQLite tutorials but can't figure it out.
The colons are among

sqlite3_prepare_v2

,

sqlite3_bind_int64

and

sqlite3_prepare_v2

statements of the below snippet.

	// delete report file
	iRet = sqlite3_prepare_v2(pDB,  "SELECT " SZ_KEY_PATH" FROM  
 "SZ_KEY_REPORT" "    "WHERE " SZ_KEY_STARTTIME "< :" SZ_KEY_NAME , 
							  -1, &pStmt, NULL);
	if (SQLITE_OK == iRet)
	{
		sqlite3_bind_int64(pStmt, sqlite3_bind_parameter_index(pStmt, ":" SZ_KEY_NAME), LocalTime - 86400 * iDelDay);
		while (SQLITE_ROW == (iRet = sqlite3_step(pStmt)))
		{
			const unsigned char* ReportPath = sqlite3_column_text(pStmt, 0);
//			Execute_Command(iRet, "echo remove %s >> /tmp/log", ReportPath);
			if (0 != (iRet = remove((const char*)ReportPath)))
			{
				goto exit_clamav_schedule;
			}
		}
		sqlite3_finalize(pStmt);
		if(SQLITE_DONE != iRet)
		{
			goto exit_clamav_schedule;
		}
	}
	iRet = sqlite3_prepare_v2(pDB,   "DELETE FROM " SZ_KEY_REPORT" "
							  "WHERE " SZ_KEY_STARTTIME" < :" SZ_KEY_NAME ,
							  -1, &pStmt, NULL);

The 'SZ_KEY_NAME' appearing in above snippet is defined as 'name' some other place of the program.

What I have tried:

I studied at SQLite tutorials in the web and discussed with my coworker but in vain.

Posted 9-May-23 20:38pm

Stan Huang

Updated 11-May-23 0:20am

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CPallini · Answer 1 · 2023-05-09T20:59:00

Solution 1

It is used to bind a variable, see for instance: https://stackoverflow.com/questions/2177978/what-does-the-colon-sign-do-in-a-sql-query[^].

Posted 9-May-23 20:59pm

CPallini

Comments

Stan Huang 11-May-23 0:15am

I am still got confused about the meaning of thme. Take the 1st sample, "iRet = sqlite3_prepare_v2(pDB, "SELECT " SZ_KEY_PATH" FROM
"SZ_KEY_REPORT" " "WHERE " SZ_KEY_STARTTIME "< :" SZ_KEY_NAME ,
-1, &pStmt, NULL);"
Since SZ_KEY_NAME is defined as 'name' and SZ_KEY_STARTTIME is defined as 'starttime', so what does
"where starttime < :name" means? ':name' means the value gotten from 'name' column?