How to retrieve the Date part out of a Datetime re

2019-02-10 15:56发布

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问题:

I have a column of datetime type from which I would like to retrieve only the date. Is there anyway to do this?

Previously it was an epoch value where I convert it to datetime .

Here is a sample result :

smbd|ip address|1082|ip address|"2011-04-26 18:40:34"

I have tried the following commands, but it yields negative / zero results

SELECT DATE(datetime) from attacked_total;
SELECT STRFTIME('%Y-%m-%d', datetime) FROM attacked_total;
SELECT DATETIME('%Y-%m-%d', datetime) FROM attacked_total;
SELECT DATE('%Y-%m-%d', datetime) FROM attacked_total;

回答1:

You can use the DATE function.

Example

> select date('2011-04-26 18:40:34')
> 2011-04-26

You can get only the day with strftime,

> select strftime('%d', '2011-04-26 18:40:34')
> 26


回答2:

This works.

SELECT strftime('%d', '2011-04-26')

You can get year, month, day and everything else that is a part of date.

But you must be carefull how you enter those strings.

The format of date is YYYY-MM-DD, so you must enter the string in that format.

It's also case-sensitive. If you want a month, then you should use %m, because if you use %M, it will try to get a minutes, and if you don't have time part in your date, it will throw an error.

For additional information check SQLite official site.



回答3:

Try looking up usage of the "datepart" function in SQL.

Something like this should work:

SELECT datewithouttime as datepart(dd,datefield)+'/'+datepart(mm,datefield)+"/"+datepart(yyyy,datefield) FROM tableName


回答4:

Try to use this functions if you are using SQLite

strftime('%Y', current_date)

strftime('%m', current_date)

strftime('%d', current_date)

strftime('%H', current_date)

strftime('%M', current_date)

strftime('%S', current_date)

In case you are using Hibernate try to register this functions in the SQLiteDialect class 

 registerFunction("year", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime('%Y', ?1))"));
    registerFunction("month", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%m', ?1))"));
    registerFunction("day", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%d', ?1))"));
    registerFunction("hour", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%H', ?1))"));
    registerFunction("minute", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%M', ?1))"));
    registerFunction("second", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%S', ?1))"));

I leave my SQLiteDialect class if you want to make any suggestions

import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.JDBCException;
import org.hibernate.ScrollMode;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.function.AbstractAnsiTrimEmulationFunction;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.SQLFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import utiles.SQLiteDialectIdentityColumnSupport;
import org.hibernate.dialect.pagination.AbstractLimitHandler;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.pagination.LimitHelper;
import org.hibernate.dialect.unique.DefaultUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.exception.DataException;
import org.hibernate.exception.JDBCConnectionException;
import org.hibernate.exception.LockAcquisitionException;
import org.hibernate.exception.spi.SQLExceptionConversionDelegate;
import org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtracter;
import org.hibernate.exception.spi.ViolatedConstraintNameExtracter;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.mapping.Column;
import org.hibernate.type.StandardBasicTypes;

/**
 * An SQL dialect for SQLite 3.
 */
public class SQLiteDialect5 extends Dialect {

    private final UniqueDelegate uniqueDelegate;

    public SQLiteDialect5() {
        registerColumnType(Types.BIT, "boolean");
        //registerColumnType(Types.FLOAT, "float");
        //registerColumnType(Types.DOUBLE, "double");
        registerColumnType(Types.DECIMAL, "decimal");
        registerColumnType(Types.CHAR, "char");
        registerColumnType(Types.LONGVARCHAR, "longvarchar");
        registerColumnType(Types.TIMESTAMP, "datetime");
        registerColumnType(Types.BINARY, "blob");
        registerColumnType(Types.VARBINARY, "blob");
        registerColumnType(Types.LONGVARBINARY, "blob");

        registerFunction("concat", new VarArgsSQLFunction(StandardBasicTypes.STRING, "", "||", ""));
        registerFunction("mod", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "?1 % ?2"));
        registerFunction("quote", new StandardSQLFunction("quote", StandardBasicTypes.STRING));
        registerFunction("random", new NoArgSQLFunction("random", StandardBasicTypes.INTEGER));
        registerFunction("round", new StandardSQLFunction("round"));
        registerFunction("substr", new StandardSQLFunction("substr", StandardBasicTypes.STRING));
        registerFunction("year", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime('%Y', ?1))"));
        registerFunction("month", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%m', ?1))"));
        registerFunction("day", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%d', ?1))"));
        registerFunction("hour", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%H', ?1))"));
        registerFunction("minute", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%M', ?1))"));
        registerFunction("second", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "abs(strftime(strftime('%S', ?1))"));
        registerFunction("trim", new AbstractAnsiTrimEmulationFunction() {
            @Override
            protected SQLFunction resolveBothSpaceTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1)");
            }

            @Override
            protected SQLFunction resolveBothSpaceTrimFromFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?2)");
            }

            @Override
            protected SQLFunction resolveLeadingSpaceTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1)");
            }

            @Override
            protected SQLFunction resolveTrailingSpaceTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1)");
            }

            @Override
            protected SQLFunction resolveBothTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1, ?2)");
            }

            @Override
            protected SQLFunction resolveLeadingTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1, ?2)");
            }

            @Override
            protected SQLFunction resolveTrailingTrimFunction() {
                return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1, ?2)");
            }
        });
        uniqueDelegate = new SQLiteUniqueDelegate(this);
    }

    // database type mapping support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    @Override
    public String getCastTypeName(int code) {
        // FIXME
        return super.getCastTypeName(code);
    }

    // IDENTITY support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    private static final SQLiteDialectIdentityColumnSupport IDENTITY_COLUMN_SUPPORT = new SQLiteDialectIdentityColumnSupport();

    @Override
    public IdentityColumnSupport getIdentityColumnSupport() {
        return IDENTITY_COLUMN_SUPPORT;
    }

    // limit/offset support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    private static final AbstractLimitHandler LIMIT_HANDLER = new AbstractLimitHandler() {
        @Override
        public String processSql(String sql, RowSelection selection) {
            final boolean hasOffset = LimitHelper.hasFirstRow(selection);
            return sql + (hasOffset ? " limit ? offset ?" : " limit ?");
        }

        @Override
        public boolean supportsLimit() {
            return true;
        }

        @Override
        public boolean bindLimitParametersInReverseOrder() {
            return true;
        }
    };

    @Override
    public LimitHandler getLimitHandler() {
        return LIMIT_HANDLER;
    }

    // lock acquisition support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    @Override
    public boolean supportsLockTimeouts() {
        // may be http://sqlite.org/c3ref/db_mutex.html ?
        return false;
    }

    @Override
    public String getForUpdateString() {
        return "";
    }

    @Override
    public boolean supportsOuterJoinForUpdate() {
        return false;
    }

    /*
    @Override
  public boolean dropTemporaryTableAfterUse() {
    return true; // temporary tables are only dropped when the connection is closed. If the connection is pooled...
  }
     */
    // current timestamp support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    @Override
    public boolean supportsCurrentTimestampSelection() {
        return true;
    }

    @Override
    public boolean isCurrentTimestampSelectStringCallable() {
        return false;
    }

    @Override
    public String getCurrentTimestampSelectString() {
        return "select current_timestamp";
    }

    // SQLException support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    private static final int SQLITE_BUSY = 5;

    private static final int SQLITE_LOCKED = 6;

    private static final int SQLITE_IOERR = 10;

    private static final int SQLITE_CORRUPT = 11;

    private static final int SQLITE_NOTFOUND = 12;

    private static final int SQLITE_FULL = 13;

    private static final int SQLITE_CANTOPEN = 14;

    private static final int SQLITE_PROTOCOL = 15;

    private static final int SQLITE_TOOBIG = 18;

    private static final int SQLITE_CONSTRAINT = 19;

    private static final int SQLITE_MISMATCH = 20;

    private static final int SQLITE_NOTADB = 26;

    @Override
    public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate() {
        return new SQLExceptionConversionDelegate() {
            @Override
            public JDBCException convert(SQLException sqlException, String message, String sql) {
                final int errorCode = JdbcExceptionHelper.extractErrorCode(sqlException);
                if (errorCode == SQLITE_TOOBIG || errorCode == SQLITE_MISMATCH) {
                    return new DataException(message, sqlException, sql);
                } else if (errorCode == SQLITE_BUSY || errorCode == SQLITE_LOCKED) {
                    return new LockAcquisitionException(message, sqlException, sql);
                } else if ((errorCode >= SQLITE_IOERR && errorCode <= SQLITE_PROTOCOL) || errorCode == SQLITE_NOTADB) {
                    return new JDBCConnectionException(message, sqlException, sql);
                }

                // returning null allows other delegates to operate
                return null;
            }
        };
    }

    @Override
    public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter() {
        return EXTRACTER;
    }

    private static final ViolatedConstraintNameExtracter EXTRACTER = new TemplatedViolatedConstraintNameExtracter() {
        @Override
        protected String doExtractConstraintName(SQLException sqle) throws NumberFormatException {
            final int errorCode = JdbcExceptionHelper.extractErrorCode(sqle);
            if (errorCode == SQLITE_CONSTRAINT) {
                return extractUsingTemplate("constraint ", " failed", sqle.getMessage());
            }
            return null;
        }
    };

    // union subclass support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    @Override
    public boolean supportsUnionAll() {
        return true;
    }

    // DDL support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    @Override
    public boolean canCreateSchema() {
        return false;
    }

    @Override
    public boolean hasAlterTable() {
        // As specified in NHibernate dialect
        return false;
    }

    @Override
    public boolean dropConstraints() {
        return false;
    }

    @Override
    public boolean qualifyIndexName() {
        return false;
    }

    @Override
    public String getAddColumnString() {
        return "add column";
    }

    @Override
    public String getDropForeignKeyString() {
        throw new UnsupportedOperationException("No drop foreign key syntax supported by SQLiteDialect");
    }

    @Override
    public String getAddForeignKeyConstraintString(String constraintName,
            String[] foreignKey, String referencedTable, String[] primaryKey,
            boolean referencesPrimaryKey) {
        throw new UnsupportedOperationException("No add foreign key syntax supported by SQLiteDialect");
    }

    @Override
    public String getAddPrimaryKeyConstraintString(String constraintName) {
        throw new UnsupportedOperationException("No add primary key syntax supported by SQLiteDialect");
    }

    @Override
    public boolean supportsCommentOn() {
        return true;
    }

    @Override
    public boolean supportsIfExistsBeforeTableName() {
        return true;
    }

    /* not case insensitive for unicode characters by default (ICU extension needed)
    public boolean supportsCaseInsensitiveLike() {
    return true;
  }
     */
    @Override
    public boolean doesReadCommittedCauseWritersToBlockReaders() {
        // TODO Validate (WAL mode...)
        return true;
    }

    @Override
    public boolean doesRepeatableReadCauseReadersToBlockWriters() {
        return true;
    }

    @Override
    public boolean supportsTupleDistinctCounts() {
        return false;
    }

    @Override
    public int getInExpressionCountLimit() {
        // Compile/runtime time option: http://sqlite.org/limits.html#max_variable_number
        return 1000;
    }

    @Override
    public UniqueDelegate getUniqueDelegate() {
        return uniqueDelegate;
    }

    private static class SQLiteUniqueDelegate extends DefaultUniqueDelegate {

        public SQLiteUniqueDelegate(Dialect dialect) {
            super(dialect);
        }

        @Override
        public String getColumnDefinitionUniquenessFragment(Column column) {
            return " unique";
        }
    }

    @Override
    public String getSelectGUIDString() {
        return "select hex(randomblob(16))";
    }

    @Override
    public ScrollMode defaultScrollMode() {
        return ScrollMode.FORWARD_ONLY;
    }
}

This is to Hibernate 5.1



标签： sql database sqlite sqlite3
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