Query builder (#10104)

* add query builder to facilitate dynamic SQL construction

* leverage query builder to refactor user store

This is partially setup work for MM-13120, but merged to master to avoid
further conflicts.

* fix unrelated unit test breakage

* documentation tweaks

* Apply suggestions from code review

Co-Authored-By: lieut-data <jesse.hallam@gmail.com>

* prefer comma separated case options to fallthrough

* vendor github.com/Masterminds/squirrel and deps

* switch to using github.com/Masterminds/squirrel

* rm querybuilder

vendor/github.com/Masterminds/squirrel/select.go

@@ -0,0 +1,348 @@
+package squirrel
+
+import (
+	"bytes"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/lann/builder"
+)
+
+type selectData struct {
+	PlaceholderFormat PlaceholderFormat
+	RunWith           BaseRunner
+	Prefixes          exprs
+	Options           []string
+	Columns           []Sqlizer
+	From              Sqlizer
+	Joins             []Sqlizer
+	WhereParts        []Sqlizer
+	GroupBys          []string
+	HavingParts       []Sqlizer
+	OrderBys          []string
+	Limit             string
+	Offset            string
+	Suffixes          exprs
+}
+
+func (d *selectData) Exec() (sql.Result, error) {
+	if d.RunWith == nil {
+		return nil, RunnerNotSet
+	}
+	return ExecWith(d.RunWith, d)
+}
+
+func (d *selectData) Query() (*sql.Rows, error) {
+	if d.RunWith == nil {
+		return nil, RunnerNotSet
+	}
+	return QueryWith(d.RunWith, d)
+}
+
+func (d *selectData) QueryRow() RowScanner {
+	if d.RunWith == nil {
+		return &Row{err: RunnerNotSet}
+	}
+	queryRower, ok := d.RunWith.(QueryRower)
+	if !ok {
+		return &Row{err: RunnerNotQueryRunner}
+	}
+	return QueryRowWith(queryRower, d)
+}
+
+func (d *selectData) ToSql() (sqlStr string, args []interface{}, err error) {
+	sqlStr, args, err = d.toSql()
+	if err != nil {
+		return
+	}
+
+	sqlStr, err = d.PlaceholderFormat.ReplacePlaceholders(sqlStr)
+	return
+}
+
+func (d *selectData) toSqlRaw() (sqlStr string, args []interface{}, err error) {
+	return d.toSql()
+}
+
+func (d *selectData) toSql() (sqlStr string, args []interface{}, err error) {
+	if len(d.Columns) == 0 {
+		err = fmt.Errorf("select statements must have at least one result column")
+		return
+	}
+
+	sql := &bytes.Buffer{}
+
+	if len(d.Prefixes) > 0 {
+		args, _ = d.Prefixes.AppendToSql(sql, " ", args)
+		sql.WriteString(" ")
+	}
+
+	sql.WriteString("SELECT ")
+
+	if len(d.Options) > 0 {
+		sql.WriteString(strings.Join(d.Options, " "))
+		sql.WriteString(" ")
+	}
+
+	if len(d.Columns) > 0 {
+		args, err = appendToSql(d.Columns, sql, ", ", args)
+		if err != nil {
+			return
+		}
+	}
+
+	if d.From != nil {
+		sql.WriteString(" FROM ")
+		args, err = appendToSql([]Sqlizer{d.From}, sql, "", args)
+		if err != nil {
+			return
+		}
+	}
+
+	if len(d.Joins) > 0 {
+		sql.WriteString(" ")
+		args, err = appendToSql(d.Joins, sql, " ", args)
+		if err != nil {
+			return
+		}
+	}
+
+	if len(d.WhereParts) > 0 {
+		sql.WriteString(" WHERE ")
+		args, err = appendToSql(d.WhereParts, sql, " AND ", args)
+		if err != nil {
+			return
+		}
+	}
+
+	if len(d.GroupBys) > 0 {
+		sql.WriteString(" GROUP BY ")
+		sql.WriteString(strings.Join(d.GroupBys, ", "))
+	}
+
+	if len(d.HavingParts) > 0 {
+		sql.WriteString(" HAVING ")
+		args, err = appendToSql(d.HavingParts, sql, " AND ", args)
+		if err != nil {
+			return
+		}
+	}
+
+	if len(d.OrderBys) > 0 {
+		sql.WriteString(" ORDER BY ")
+		sql.WriteString(strings.Join(d.OrderBys, ", "))
+	}
+
+	if len(d.Limit) > 0 {
+		sql.WriteString(" LIMIT ")
+		sql.WriteString(d.Limit)
+	}
+
+	if len(d.Offset) > 0 {
+		sql.WriteString(" OFFSET ")
+		sql.WriteString(d.Offset)
+	}
+
+	if len(d.Suffixes) > 0 {
+		sql.WriteString(" ")
+		args, _ = d.Suffixes.AppendToSql(sql, " ", args)
+	}
+
+	sqlStr = sql.String()
+	return
+}
+
+// Builder
+
+// SelectBuilder builds SQL SELECT statements.
+type SelectBuilder builder.Builder
+
+func init() {
+	builder.Register(SelectBuilder{}, selectData{})
+}
+
+// Format methods
+
+// PlaceholderFormat sets PlaceholderFormat (e.g. Question or Dollar) for the
+// query.
+func (b SelectBuilder) PlaceholderFormat(f PlaceholderFormat) SelectBuilder {
+	return builder.Set(b, "PlaceholderFormat", f).(SelectBuilder)
+}
+
+// Runner methods
+
+// RunWith sets a Runner (like database/sql.DB) to be used with e.g. Exec.
+func (b SelectBuilder) RunWith(runner BaseRunner) SelectBuilder {
+	return setRunWith(b, runner).(SelectBuilder)
+}
+
+// Exec builds and Execs the query with the Runner set by RunWith.
+func (b SelectBuilder) Exec() (sql.Result, error) {
+	data := builder.GetStruct(b).(selectData)
+	return data.Exec()
+}
+
+// Query builds and Querys the query with the Runner set by RunWith.
+func (b SelectBuilder) Query() (*sql.Rows, error) {
+	data := builder.GetStruct(b).(selectData)
+	return data.Query()
+}
+
+// QueryRow builds and QueryRows the query with the Runner set by RunWith.
+func (b SelectBuilder) QueryRow() RowScanner {
+	data := builder.GetStruct(b).(selectData)
+	return data.QueryRow()
+}
+
+// Scan is a shortcut for QueryRow().Scan.
+func (b SelectBuilder) Scan(dest ...interface{}) error {
+	return b.QueryRow().Scan(dest...)
+}
+
+// SQL methods
+
+// ToSql builds the query into a SQL string and bound args.
+func (b SelectBuilder) ToSql() (string, []interface{}, error) {
+	data := builder.GetStruct(b).(selectData)
+	return data.ToSql()
+}
+
+func (b SelectBuilder) MustSql() (string, []interface{}) {
+	sql, args, err := b.ToSql()
+	if err != nil {
+		panic(err)
+	}
+	return sql, args
+}
+
+func (b SelectBuilder) toSqlRaw() (string, []interface{}, error) {
+	data := builder.GetStruct(b).(selectData)
+	return data.toSqlRaw()
+}
+
+// Prefix adds an expression to the beginning of the query
+func (b SelectBuilder) Prefix(sql string, args ...interface{}) SelectBuilder {
+	return builder.Append(b, "Prefixes", Expr(sql, args...)).(SelectBuilder)
+}
+
+// Distinct adds a DISTINCT clause to the query.
+func (b SelectBuilder) Distinct() SelectBuilder {
+	return b.Options("DISTINCT")
+}
+
+// Options adds select option to the query
+func (b SelectBuilder) Options(options ...string) SelectBuilder {
+	return builder.Extend(b, "Options", options).(SelectBuilder)
+}
+
+// Columns adds result columns to the query.
+func (b SelectBuilder) Columns(columns ...string) SelectBuilder {
+	var parts []interface{}
+	for _, str := range columns {
+		parts = append(parts, newPart(str))
+	}
+	return builder.Extend(b, "Columns", parts).(SelectBuilder)
+}
+
+// Column adds a result column to the query.
+// Unlike Columns, Column accepts args which will be bound to placeholders in
+// the columns string, for example:
+//   Column("IF(col IN ("+squirrel.Placeholders(3)+"), 1, 0) as col", 1, 2, 3)
+func (b SelectBuilder) Column(column interface{}, args ...interface{}) SelectBuilder {
+	return builder.Append(b, "Columns", newPart(column, args...)).(SelectBuilder)
+}
+
+// From sets the FROM clause of the query.
+func (b SelectBuilder) From(from string) SelectBuilder {
+	return builder.Set(b, "From", newPart(from)).(SelectBuilder)
+}
+
+// FromSelect sets a subquery into the FROM clause of the query.
+func (b SelectBuilder) FromSelect(from SelectBuilder, alias string) SelectBuilder {
+	return builder.Set(b, "From", Alias(from, alias)).(SelectBuilder)
+}
+
+// JoinClause adds a join clause to the query.
+func (b SelectBuilder) JoinClause(pred interface{}, args ...interface{}) SelectBuilder {
+	return builder.Append(b, "Joins", newPart(pred, args...)).(SelectBuilder)
+}
+
+// Join adds a JOIN clause to the query.
+func (b SelectBuilder) Join(join string, rest ...interface{}) SelectBuilder {
+	return b.JoinClause("JOIN "+join, rest...)
+}
+
+// LeftJoin adds a LEFT JOIN clause to the query.
+func (b SelectBuilder) LeftJoin(join string, rest ...interface{}) SelectBuilder {
+	return b.JoinClause("LEFT JOIN "+join, rest...)
+}
+
+// RightJoin adds a RIGHT JOIN clause to the query.
+func (b SelectBuilder) RightJoin(join string, rest ...interface{}) SelectBuilder {
+	return b.JoinClause("RIGHT JOIN "+join, rest...)
+}
+
+// Where adds an expression to the WHERE clause of the query.
+//
+// Expressions are ANDed together in the generated SQL.
+//
+// Where accepts several types for its pred argument:
+//
+// nil OR "" - ignored.
+//
+// string - SQL expression.
+// If the expression has SQL placeholders then a set of arguments must be passed
+// as well, one for each placeholder.
+//
+// map[string]interface{} OR Eq - map of SQL expressions to values. Each key is
+// transformed into an expression like "<key> = ?", with the corresponding value
+// bound to the placeholder. If the value is nil, the expression will be "<key>
+// IS NULL". If the value is an array or slice, the expression will be "<key> IN
+// (?,?,...)", with one placeholder for each item in the value. These expressions
+// are ANDed together.
+//
+// Where will panic if pred isn't any of the above types.
+func (b SelectBuilder) Where(pred interface{}, args ...interface{}) SelectBuilder {
+	if pred == nil || pred == "" {
+		return b
+	}
+	return builder.Append(b, "WhereParts", newWherePart(pred, args...)).(SelectBuilder)
+}
+
+// GroupBy adds GROUP BY expressions to the query.
+func (b SelectBuilder) GroupBy(groupBys ...string) SelectBuilder {
+	return builder.Extend(b, "GroupBys", groupBys).(SelectBuilder)
+}
+
+// Having adds an expression to the HAVING clause of the query.
+//
+// See Where.
+func (b SelectBuilder) Having(pred interface{}, rest ...interface{}) SelectBuilder {
+	return builder.Append(b, "HavingParts", newWherePart(pred, rest...)).(SelectBuilder)
+}
+
+// OrderBy adds ORDER BY expressions to the query.
+func (b SelectBuilder) OrderBy(orderBys ...string) SelectBuilder {
+	return builder.Extend(b, "OrderBys", orderBys).(SelectBuilder)
+}
+
+// Limit sets a LIMIT clause on the query.
+func (b SelectBuilder) Limit(limit uint64) SelectBuilder {
+	return builder.Set(b, "Limit", fmt.Sprintf("%d", limit)).(SelectBuilder)
+}
+
+// Limit ALL allows to access all records with limit
+func (b SelectBuilder) RemoveLimit() SelectBuilder {
+	return builder.Delete(b, "Limit").(SelectBuilder)
+}
+
+// Offset sets a OFFSET clause on the query.
+func (b SelectBuilder) Offset(offset uint64) SelectBuilder {
+	return builder.Set(b, "Offset", fmt.Sprintf("%d", offset)).(SelectBuilder)
+}
+
+// Suffix adds an expression to the end of the query
+func (b SelectBuilder) Suffix(sql string, args ...interface{}) SelectBuilder {
+	return builder.Append(b, "Suffixes", Expr(sql, args...)).(SelectBuilder)
+}